Because Sumana demanded it...

Effects of Sleep Deprivation

(In all these tables, negative numbers are penalties, positive numbers are bonuses. You will probably have to adjust them to your roleplaying system. Henceforth, "you" refers to your character.)

When you wake up, and once an hour thereafter, roll percentile dice. Reduce the result modulo the total number of hours you have been awake, minimum five, modified as described below. Then add ten for each day you have been awake, maximum thirty. Use the value to index the main table. If you go over the top, subtract 100, add ten for each day again, and repeat. You suffer whatever effect is described in that entry, for one hour. A roll of 00 is zero, not 100.

If you are suffering fatigue modifiers due to physical or mental exertion, treat each point of penalty as an extra hour awake. If you are suffering from stun damage, treat each point of penalty as an extra eight hours. This does not affect the number of days you are deemed to have been awake.

If the player is too tired to follow the above instructions, then roll percentiles, divide by two, and add whatever the GM tells you to add. (We recommend that the GM pick a number between 20 and 50 in this circumstance.)

Effects marked s can be mitigated by mild stimulants such as coffee. However, coffee is less and less effective as you have been awake longer:

Time awake Duration of mitigation
0-8 hours 3 hours
8-16 1 hour
16-24 30 minutes
24-36 15 minutes
36+ Ineffective

Also, if you consume more than two cups of coffee per hour, roll a d10 against this table for each additional cup:

Roll Effect
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 Roll percentile dice and look up the result in the main table; take the nearest effect marked c. Do not reduce or modify this roll as you do for the once-per-hour check. The effect is in addition to any others, and lasts for a full hour.

Past 24 hours awake, roll against this table for every cup of coffee consumed.

All coffee penalties are cumulative. Penalties wear off at a rate of one point per hour without any stimulant consumed. You will be unable to fall asleep until all penalties have worn off; in any case you cannot fall asleep for two hours after drinking coffee (even if the main table says you do; treat any such roll as equivalent to 00, and additional coffee will not help).

Without further ado:

00 sYou are groggy. -1 to all mental actions.
01 s " "
02 s " "
03 No effect.
04 " "
05 " "
06 sYou move slowly. -1 to initiative.
07 cYou are antsy. -1 to sit still. -1 to refuse any suggestion of physical activity.
08 No effect.
09 " "
10 cMake a willpower check or spend the entire hour doing something pointless.
11 sYour eyes do not want to focus.
12 sYou move slooowly. -3 to initiative.
13 Everyone sounds like they are mumbling. -2 to comprehend what other people say.
14 cYou are hyper. +1 to initiative. -1 to attention span.
15 cBright light is painful.
16 sYou keep almost falling asleep.
17 You have trouble remembering the word you need next in your sentence.
18 sYour brain has been replaced with a sponge. -2 to all mental actions.
19 You can't manage to enunciate. -2 to anyone else trying to understand you.
20 Any unexpected noise makes you jump.
21 You cannot do basic arithmetic (-4 penalty)
22 You keep dropping off for a minute or so (this does not help any)
23 All actions take twice as long as they should.
24 cYou are severely hyper. -2 to attention span. Initiative is a wash.
25 Everything is funny. -1 to avoid cracking up.
26 cDistractions fall away. +2 to concentration and mental activity. -2 to notice anything going on around you.
27 Keeping your eyes focussed is painful.
28 cYou have a screaming case of the munchies.
29 Rock'n'roll lyrics make sense.
30 You doze off for an hour and wake up feeling surprisingly refreshed; subtract five hours from your current lack-of-sleep tally.
31 You are stressed out for no reason.
32 cEverything is hilarious. -3 to avoid cracking up.
33 You are depressed for no reason.
34 sYou keep dropping off for ten minutes or so (this does not help any).
35 sAll actions take three times as long as they should.
36 sYou move sloooooowly. -6 to initiative.
37 Any unexpected noise or movement brings on a full-fledged panic attack.
38 cYou have severe jitters. -3 to all fine motor movements.
39 You put things down in midair and are surprised when they fall.
40 Having your eyes open is painful.
41 cYou're dizzy. -1 to walk.
42 You cannot keep your eyes focussed, no matter how hard you try.
43 cYou are seeing double.
44 Your body feels like it belongs to someone else.
45 sYour brain has been replaced with dryer lint. -3 to all mental actions.
46 You take anything anyone says to you as an excuse to start an argument.
47 cYou're wide awake and just fine!
48 Are the walls moving?
49 Having eyes is painful.
50 You fall asleep, but can be awakened (in which case you are groggy, as if you got 00).
51 You keep thinking you saw a rabbit hiding behind something.
52 cYou just got up and went to the kitchen, but you can't remember why.
53 You have an urge to juggle nearby objects, even though you don't know how.
54 cYou have vertigo. -2 to move at all.
55 You babble uncontrollably.
56 You put things down on solid surfaces and are surprised when they don't fall.
57 The world looks like a Monet painting.
58 The person next to you appears to be a rabbit.
59 The person next to you appears to be a giant sack of flour.
60 You're freezing cold, and you have no idea why.
61 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.
62 cYour short term memory is nonfunctional. -4 to maintain a train of thought.
63 sAll actions take ten times as long as they should.
64 You keep getting lost, even in totally familar surroundings.
65 Everything looks like it's about to fall over.
66 General relativity makes sense.
67 A nearby piece of furniture is talking to you.
68 cAny unexpected event whatsoever brings on a full-fledged panic attack.
69 You have achieved zanshin, the state of no-mind. You act without needing to think first. (+2 to initiative and all physical actions; -2 to act other than on reflex)
70 The world looks like a Magritte painting.
71 cEverything and everyone is indeed out to get you.
72 ARGH! GIANT RABBIT! You attempt to kill it, using whatever is convenient.
73 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.
74 You can hear the ticking of the gears in your head as you think.
75 Advanced philosophy makes sense.
76 You are stressed out beyond belief, and snap at anyone who says anything to you.
77 You forget the ends of your sentences halfway through.
78 The world looks like a Picasso painting.
79 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.
80 You have an uncontrollable urge to repair something.
81 Shadows on the nearby walls begin to move, acting out a complex play. The room is still.
82 cThere are bugs crawling on everything. EVERYTHING.
83 Quantum electrodynamics makes sense.
84 A short, bald fellow in brown clothes, carrying a shotgun, inquires whether you have seen any wabbits around here?
85 You understand foreign languages you have never heard before. Which is a good thing, because everyone around you is speaking one.
86 cYou have severe vertigo. -4 to move at all.
87 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.
88 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.
89 You have a full-fledged panic attack...yes, for an entire hour.
90 Somewhere, bells are ringing, and you must find them.
91 You can hear the ticking of the gears of the clock that drives the universe. You feel insignificant next to such immensity.
92 You are much too big for this room. Your head is scraping the ceiling; your arms can reach both walls at once.
93 The world looks like a Kandinsky painting.
94 You become obsessed with whatever it is you are currently doing, and must continue for the next hour without interruption.
95 cThere is an incredibly vile taste in your mouth, which you cannot get rid of.
96 The phone rings; it's someone you know to be dead.
97 Post-modern literary criticism makes sense.
98 You are face-to-face with Rabbit himself, the totem spirit, the Prince with a Thousand Enemies. His ears glow faintly of starlight. You hear him whisper to you the secrets of the universe.
99 You fall asleep and cannot be awakened for any reason, for eight hours times the number of days you have been awake.