I don't know if it's still on the forums over at Order of the Stick, but there is a classic list entitled "250 things Mr. Welch can no longer do in an RPG."
As I am not Mr. Welch, I cannot attest to when and where these things happened, but he did detail them out in the thread. They cover all genres of gaming and multiple systems in each genre. Here are about half of the listings:
2. A one man band is not an appropriate bard instrument.
3. There is no Gnomish god of heavy artillery.
6. Synchronized panicking is not a proper battle plan.
7. Not allowed to use psychic powers to do the dishes.
8. How to serve Dragons is not a cookbook.
9. My monk's lips must be in sync.
11. Not allowed to berserk for the hell of it, especially during royal masquerades.
14. Ogres are not kosher.
15. Plan B is not automatically twice as much gunpowder as Plan A.
17. Collateral Damage Man is not an appropriate name for a super hero.
19. Drow are not good eating.
20. Polka is not appropriate marching music.
22. There is no such thing as a Gnomish Pygmy War Rhino.
25. The green elf does not need food badly.
26. Valley speak has no place in a fantasy setting. Especially if you're the paladin.
32. I cannot buy any animal in groups of 100 or over.
33. There is no such skill as 'improvised cooking'
35. I am not allowed to convince the entire party to play R2 units.
37. They do not make black market illegal cyberweapons for rodents.
44. Not allowed to spend all 100 character points on 100 1pt skills.
45. My character names are not allowed to be double entendres.
48. The elf is restricted to decaf for the rest of the adventure.
51. No longer allowed to use the time machine for booty calls.
52. My bard does not know how to play Inna Godda Davida on marachas.
53. Not allowed to start a drow character weighing more than a quarter ton.
55. Before facing the dragon, not allowed to glaze the elf.
57. In the middle of a black op I cannot ask a guard to validate parking.
60. Not allowed to short sheet the bedroll of impotent dieties.
63. No, I cannot buy 10,000 marbles even if I say please.
64. My paladin's battle cry is not "Good for the Good God"
67. There is no Kung Fu manuever "McGuire Swings For Bleachers"
71. There is no 'annoy' setting on a phasor
74. My thief's battle cry is not "Run And Live"
75. Nor is it "You take care of the orcs, I take care of the traps"
78. Not allowed to commission a pistol that costs more than a sedan.
80. When accepting a challenge for a duel, I must allow the other guy time to find a pistol.
81. A picture of my ex-wife is not an acceptable backup weapon.
82. Victory laps after killing the dragon with my 1d2 bow is considered in poor taste.
83. My gnome does not like big butts and he cannot lie.
88. My bard does not get a bonus to perform if she is obviously not wearing anything under her tabard.
91. A wet towel does not constitute an improvised weapon.
92. The name of the weapon shop is not "Bloodbath and Beyond"
97. My one wish cannot be 'I wish everything on this piece of paper was true'
99. Not allowed to see if Jedi can parry a shotgun blast with their lightsaber.
101. I am not allowed to pave ANYTHING.
103. There is no such thing as a Club +3 of Cup Checks
104. Nor is there a +1 Longsword, +5 against party members.
106. I do not have weapon profiency in cat.
107. There is no such game as Wereshark the Buffet.
114. The Demilich only falls for getting stuffed in the bag of holding once.
117. I am restricted to memorizing Floating Disc only once per day.
118. I will pick a more traditional paladin weapon instead of a sledgehammer.
120. Not allowed to kill another party member with a boomerang again.
124. I cannot insert the words "Kill Phil, Sorry Phil" into any list of instructions.
126. Dwarves do not count as burrowing animals.
127. Not allowed to download AOL 6.0 on the Arasaka mainframe.
131. Not allowed to bet how many times the lich bounces.
133. My acrobat cannot balance on the warlord's head for more than one round.
137. I do not have a scorching case of lycanthropy.
138. If the mere thought of it costs the others sanity, I'm forbidden from doing it.
142. Not allowed to give a 4 year old a sugar rush just to jack up the CR later.
144. There is no such thing as pleather armor.
147. Hobbits are not allowed to have Norse ancestry.
148. There is no Gnomish Deathgrip, and even if there was, it wouldn't involve tongs.
153. I will not propose to every noblewoman at the royal ball until I crit my charisma check.
154. I am not allowed to rub the monk's head for luck.
158. I will not declare myself a god just so I can grant myself spells.
162. What ever monster we just killed is not to be tonight's dinner.
164. I am not to tattle to the halfling assassin's mom about his career choice.
171. My character's dying words are not allowed to be "Hastur, Hastur, Hastur"
172. At no point can I justify spending force points on a seduction check.
174. There is no use of Shatner's spoken word album that doesn't require a humanity check.
178. There are no profanities in Celestial.
181. I cannot quote Shakespeare in Crinos.
183. There are no rules for cooking corn dogs in any d20 supplement.
185. My bard does not need roadies for a dungeon crawl.
186. No cutting line to be a god.
190. Duel wielding small animals is strictly forbidden.
194. When the other guy picks swords for the choice of weapons, that does not leave me pistols.
195. I cannot use a silent feat enambled power word stun and blame it on the dog.
198. Not allowed to steal my own soul.
201. My thief is prohibited from speaking solely in Cant.
203. My superhero's strength is not classified as snazzy, neato or bodacious.
204. I am not too sexy for the elf, too sexy for the elf, so sexy myself.
207. The following weapons are not legal choices in a duel: Steamroller, Nerve Gas, Landmine, Midget.
211. If at any point if my dwarf takes on the mannerisms of Macho Man Randy Savage, he dies.
213. I am not the patron saint of common sense.
214. There is no prestige class Drizzt Slayer.
218. No matter my alignment, organizing halfling pit fights is a violation.
221. If I get that Yugo up to 120mpg again, that's gonna get some paradox.
222. Druids are not against my religion.
224. I cannot insinuate elf chicks are all easy, even though you never hear about a half gnome do you?
227. My last wish cannot be "I wish we were playing another game."
230. There is no such thing as monofilament tooth floss.
231. I am not allowed to do anything that would make a Sith Lord cry.
234. My character does not get d34 HP a level.
236. My character has no need for 24,000 cartons of cigarettes, especially in his neighbor's garage.
241. Cannot use the jedi mind trick to get out of a speeding ticket.
242. Not allowed to give quicklings Mountain Dew.
243. Cannot cast haste on the king during a long winded speech to get him to hurry the hell up.
247. If the king rewards me with a forest, I am to assume he intends for me to keep it a forest.
248. There is no Halfling god of groin shots.
I'll post the full list if anyone is interested.