Many RPGs have some basic notion of fatigue penalties, but they lack color. On the more cyberpunk end of the spectrum, you got to figure the PCs are regularly sneaking around late at night. It’s harder to stay awake for days on end in a setting without electric light, but players still do come up with those sneaky plans that involve, well, sneaking around late at night. There’s tons of amusement value being left on the table due to a lack of fleshed-out-ness.

Conventions

I assume that your RPG system has some (probably dice-based) mechanism for deciding whether an action succeeds, subject to numeric modifiers. In this supplement, positive modifiers are bonuses, negative modifiers are penalties, and the smallest possible modifier is ±1.

Modifiers apply to some subset of actions, described after the number. For instance, −1 to mental actions means a penalty of 1 to every action that involves thinking. Since this is a generic supplement, I avoid talking about specific character statistics. One exception: initiative is the mechanism for deciding who gets to act first in adversarial situations (e.g. combat).

From this point on, you refers to the character suffering sleep deprivation.

Tracking sleep deprivation

You have a new statistic: the amount of sleep you require. The default for this is the requirement for normal adult humans: eight hours per 24-hour day. When you don’t make your sleep requirement, you accumulate an hour of sleep debt for every extra hour fully awake. You must spend extra time asleep in the future to pay off the debt. Until then, you are subject to penalties.

Even if you spend all the necessary time resting, you might not make your full sleep quota for various reasons: light, noise, vibration, chronic pain, uncomfortable position or surface, etc. For simplicity, we just say that eight hours of disturbed sleep, whatever the cause, is equivalent to seven hours of fully restful sleep.

If you wake up in the middle of a sleep cycle and remain awake for more than a few minutes, that is interrupted sleep. Interrupted sleep is not as bad as not sleeping at all, but not as good as continuous sleep. For each hour of wakefulness inside a sleep cycle that, taken as a whole, meets your sleep requirement, you suffer half an hour of sleep debt.

Sleeping too much can also add sleep debt, by throwing off your circadian rhythm. This is at the GM’s discretion, but should never add more than an hour of debt in total.

Sleep debt is repaid at a rate of one hour per sleep cycle, plus two hours for every extra hour of sleep. It cannot be repaid faster than six hours per sleep cycle, under normal circumstances (see below). Thus, an adult human who regularly gets only seven hours of sleep a night will remain at one hour of sleep debt indefinitely, and a single all-nighter will take at least two days to recover from.

If you deliberately go to sleep (for any period) while suffering more than 24 hours of sleep debt, you might collapse from exhaustion! See below.

Permanent modifiers

If your basic sleep requirement is permanently different from the norm of 8 consecutive undisturbed hours per 24-hour day, you have a character advantage or disadvantage, requiring a rationale and subject to GM approval. For instance:

• You are a robot, so you need no sleep at all. (Racial advantage.)
• Thanks to a quirk of genetics, you need only six hours of sleep a night. (Personal advantage purchased at character creation.)
• You suffer insomnia: all your sleep is interrupted, and you can sleep no more than 1d4−1 extra hours a day (roll daily) to make up for it. (Personal disadvantage sold at character creation.)
• Cybernetic modifications allow you to derive full rest from interrupted sleep, and delay sleep for up to 48 hours with no penalty, but you must still get 24 hours of sleep in any 72-hour period. (Personal advantage, can be purchased as an upgrade.)

Stimulants

Anything that compensates temporarily for sleep debt is a stimulant. Stimulants have two statistics: strength and duration, both measured in hours. When you use a stimulant, your effective sleep debt is reduced by the stimulant’s strength, for its duration. Here are some sample stimulants:

• Regular coffee, caffeinated soda: strength 1, duration 4
• Double espresso, No-Doz: strength 3, duration 4
• Amphetamines: strength 5, duration 5

These all happen to be chemicals, but cybernetic stimulant chips, magical sleep compensation, and whatever else you can think of should fit into these rules as well.

Strength stacks, but duration does not. Thus, two cups of coffee and a shot of speed will compensate for seven hours of sleep debt, but only for four hours; then the coffee wears off and you’re left with five hours’ compensation for the remaining hour that the amphetamines are effective.

Stimulants become less effective if used habitually: adjustments are at the GM’s discretion, but as a guideline, daily use should start reducing the duration after a couple weeks, and more-than-daily use should eventually reduce the strength. A serious stimulant habit will trigger withdrawal symptoms when you stop; again, as a guideline, one extra hour of sleep debt for every week of habitual use, which you are stuck with for at least one week.

You cannot fall asleep while under the influence of stimulants, unless the effect tables say you do.

Sleep enhancers

There are two kinds of sleep enhancer. One kind simply converts disturbed or interrupted sleep into normal sleep: for instance, anti-insomnia medicine. Another kind allows you to pay off sleep debt faster, by raising the six hours of recovery per cycle cap and/or allowing each hour of sleep under the influence to pay off more than one hour of debt. There are no real-world drugs with this effect, but in a high-tech future there certainly could be, likewise healing magic.

Naps

Taking a nap in the middle of a day is surprisingly helpful. If you intentionally nap for one hour, that will subtract 1d4 hours from your sleep debt. However, if you have at least 8 hours of sleep debt, you might collapse from exhaustion.

You cannot nap while under the influence of stimulants, and for simplicity’s sake, you cannot nap for more than an hour—it becomes a regular interrupted sleep cycle.

Collapse from exhaustion

When your limbic system just will not permit any more time awake, you collapse. This happens in three different circumstances:

• If the major sleep deprivation effect table says so.
• If you have at least 8 hours of sleep debt, attempt to nap, and roll 4 on the d4.
• If you have at least 24 hours of sleep debt, you must flip a coin when you go to sleep for any length of time, whether deliberately or because of a deprivation effect. If it’s tails, you’ve collapsed.

However it happens, once you collapse you will remain asleep for as many hours as your total sleep debt, unless forcibly awakened. External stimuli that would normally be sufficient to cause disturbed sleep are not enough to wake up someone who has collapsed. A bucket of ice water will do it, though.

If forcibly awakened, the collapse does not help at all. If you are allowed to wake up on your own, however, your sleep debt is reset to two hours.

Interaction with other game mechanics

You can either treat the sleep-debt mechanic as separate from other sources of fatigue penalties in your game system, or you can combine them. If you combine them, I recommend converting fatigue penalties to additional hours of effective sleep debt at a ratio of one to two, but continuing to let them wear off as specified in your core rule set. For instance, a PC who pulled an all-nighter for eight hours of true sleep debt, and then played a strenuous basketball game which put them at −2 due to fatigue, would suffer 12 hours of effective sleep debt instead of the −2 penalty, but four of those hours would wear off as specified for the original penalty instead of being paid back by extra sleep.

Effects

With at least one hour of effective sleep debt (that is, after subtracting stimulant strength and adding other fatigue modifiers) you suffer a −1 penalty to all mental actions. Every additional two hours of sleep debt adds another −1 to mental actions, to a maximum of −4.

With at least two hours of effective sleep debt, you suffer a −1 penalty to all physical actions. Again, every additional two hours adds another −1, to a maximum of −4.

With at least three hours of effective sleep debt, you must, once every hour that you remain awake, roll against the master sleep effects table. This table directs you to the specific effect tables. Follow the instructions in the Tables section, below.

If you are on stimulants, you must, once an hour, roll against the stimulant effects table.

All effects stack; a character with maxed-out basic penalties can and will suffer additional penalties from the sleep debt and stimulant tables.

Effect Tables

Effects last for a full hour unless otherwise specified.

Master Sleep Debt Table

Roll 1d4 and add one-third of your effective sleep debt, rounded down. For each effect listed, go to the appropriate table below and follow the instructions.

1. : None
2. : None
3. : One minor effect
4. : One minor effect
5. : Two minor effects
6. : One moderate effect
7. : One minor and one moderate effect
8. : One major effect
9. : One moderate and one major effect 10+. : Two major effects

Stimulant Effects

Divide the total strength of all stimulants you are on by three, and roll that many d10s. You suffer all of the effects rolled, for a full hour.

1–4.

No effect. 5–6.

Shaky hands. −1 to all fine motor actions. 7–8.

Attention deficit. −1 to all mental actions. 9.

Hyperfocus. +1 to actions requiring concentration, −1 to notice anything going on around you. 0.

One moderate sleep effect.

Minor Effects

Roll 1d20.

1. You react slowly. −1 to initiative.
2. You react sloooowly. −3 to initiative.
3. Your eyes do not want to focus.
4. Everyone sounds like they are mumbling. −2 to understand them.
5. You can’t manage to enunciate. Other people are at −2 to understand you.
6. You keep almost falling asleep.
7. You keep dropping off for a minute or so (this does not help any).
8. You have trouble remembering the word you need next in your sentences. Speaking is not a free action.
9. You are hyper. −2 to attention span.
10. Everything is funny. −1 to avoid cracking up.
11. Everything is hilarious. −3 to avoid cracking up.
12. Any unexpected noise makes you jump.
13. All actions take twice as long as they should.
14. You keep getting lost, even in totally familar surroundings.
15. Keeping your eyes focused is painful. −1 to any action that involves looking at anything.
16. You have severe jitters; −3 to fine motor movements.
17. You are dizzy. −1 to walk.
18. You are antsy. −1 to sit still. −1 to refuse any suggestion of physical activity.
19. Distractions fall away. +2 to concentration and mental activity. −2 to notice anything going on around you.
20. Roll a moderate effect. (If you came here from the moderate effects table, reroll on this one instead.)

Moderate Effects

Roll 1d20.

1. Roll a minor effect. (If you came here from the minor effects table, reroll on this one instead.)
2. You react sloooooooowly. −6 to initiative.
3. You keep dropping off for ten minutes or so (this does not help any).
4. You doze off for an hour. This counts as a nap.
5. You are antsy. −1 to sit still. −1 to refuse any suggestion of physical activity.
6. You are hyper. −2 to attention span.
7. You cannot maintain a train of thought. Additional −2 (on top of mental action penalties) to do anything that requires a sequence of actions.
8. Make a willpower check or spend the entire hour doing something pointless.
9. Bright light is painful. −1 to visual tasks in brightly lit areas.
10. Keeping your eyes focused is painful. −1 to any action that involves looking at anything.
11. You cannot keep your eyes focused, no matter how hard you try. −2 to any action that involves looking at anything.
12. You have vertigo. −2 to move without falling over.
13. You are stressed out.
14. You are depressed.
15. You’re freezing cold.
16. You have a screaming case of the munchies.
17. You cannot stop cracking jokes. −1 to social interaction; you’re too tired to be funny.
18. You take anything anyone says to you as an excuse to start an argument.
19. You continually ramble away from the topic of conversation.
20. Roll a major effect. (If you came here from the major effects table, reroll on this one instead.)

Major Effects

Roll 1d20.

1. Roll a moderate effect. (If you came here from the moderate effects table, reroll on this one instead.)
2. You have achieved zanshin, the state of no-mind. For this hour, all current penalties for physical action are suspended; instead you have a bonus of +2 for physical action, and a +2 to initiative. However, you are at an additional −2 on top of current mental penalties to act other than on reflex. (This will not be a problem for skilled fighters and others who have trained to take the proper action by reflex.)
3. All actions take ten times as long as they should.
4. Having eyes is painful. −1 to everything.
5. You have severe vertigo. −4 to move without falling over.
6. You put things down in midair and are surprised when they fall.
7. You put things down on solid surfaces and are surprised when they don’t fall.
8. You have an urge to juggle nearby objects, whether or not you know how.
9. You have an urge to repair or at least disassemble something, again whether or not you know how.
10. You are hypnotized by a nearby small object and cannot do anything but examine it. If someone takes it away from you, you find another one to fixate on.
11. You become obsessed with whatever it is you are currently doing, and must continue for the next hour without interruption.
12. Any unexpected event whatsoever brings on a full-fledged panic attack.
13. You are stressed out beyond belief, and snap at anyone who says anything to you.
14. Everything and everyone is indeed out to get you.
15. Roll a hallucination every 30 minutes.
16. Roll a hallucination every 20 minutes.
17. Roll a hallucination every 10 minutes.
18. Roll a hallucination every 5 minutes.
19. You doze off for an hour. This counts as a nap.
20. You collapse from exhaustion.

Hallucinations

Roll 1d20. Hallucinations last until the next hallucination or effect roll. The GM should elaborate on them so they don’t get repetitive. Making up your own hallucination table is encouraged.

1. The world looks like a Monet painting.
2. You keep thinking you saw a rabbit hiding behind something.
3. You can see the auras of living things. +1 to empathy; −1 to physical actions, due to disorientation. If you already have this ability, you find you can’t turn it off.
4. A nearby piece of furniture is talking to you.
5. You can hear the ticking of the gears in your head as you think.
6. Advanced philosophy makes sense.
7. ARGH! GIANT RABBIT! You have an urge to try to kill it, using whatever is convenient.
8. Shadows on the nearby walls begin to move, acting out a complex play. The room is still.
9. Quantum chromodynamics makes sense.
10. A short, bald fellow in brown clothes, carrying a shotgun, inquires whether you have seen any wabbits around here?
11. You understand foreign languages you have never heard before. Which is a good thing, because everyone around you is speaking one.
12. You put out your hands and fall through the window. Clawing at nothing, you drop through the void; your terrified screams are inaudible, drowned in the spiral ahead.
13. You can hear the ticking of the gears of the clock that drives the universe. You feel insignificant next to such immensity.
14. You see a white rabbit with pink eyes about ten feet away. It takes a watch out of its waistcoat pocket, looks at it, exclaims Oh dear! I shall be too late! and dives down a hole.
15. You are much too big for this room. Your head is scraping the ceiling; your arms can reach both walls at once.
16. Your phone rings; it’s someone you know to be dead.
17. You doze off for a few minutes; when you awake you discover that everything around you has been removed and replaced with an exact duplicate.
18. Post-modern literary criticism makes sense.
19. There are bugs crawling on everything. EVERYTHING.
20. You are in the presence of the Prince with a Thousand Enemies. His ears glow faintly of starlight. You hear him whisper to you the secrets of the universe.

Author’s Note

The original version of this supplement was written in December 2002, as an exercise in pure silliness instigated by Sumana. This marginally less silly version occurred to me as a way of getting my writerly brain back in gear after a long time doing nothing but coding.

As always, fabulous no-prizes are available to those who spot the references.