First, Jeff Rients came up with this famous table for carousing mishaps. Then I found the old article on orgies from Dragon Magazine (warning NSFW cartoonage). Ideas were gained.
Your character doesn't like to level up by partying like Conan? Not a problem. Check out Martial training, holy Sacrifice, and Esoteric research. But if wine and wenches is your bag, check out the system below.
When you perform this leveling action, you must roll a Carousing check (1d20+ luck mod, DC 15 for success), spend your gold (which becomes XP), then role-play through the results (though the DM can just tell you what happened). Success nets you a roll on the right side of the following table as a kind of bonus to the joy of getting XP.
Failure means nothing special, but rolling a 1 means you have to roll on the left side of the table!
1. Gain reputation as a lecherous lush. Social interactions in this town are *raises tone* awkward.
2. Get in a fight, lose 1d2 teeth, get a black eye, or break your nose and you'll be sore (-1d3 hp) in the morning.
3. Wake up next to someone ugly or crazy (50-50 chance) or both (5% chance). Lose reputation.
4. Alcohol poisoning. Constitution/stamina lowered by 1.
5. Things got a little crazy. Did we kill the stripper?! Move you alignment one step towards evil/chaos. Can be undone by Sacrifice carousing.
6. Insulted someone important, and challenged to a duel if you are equals or charged with a quest if you are the inferior.
7. Someone takes your bag by mistake, but leaves theirs, which has an interesting item...
8. A couple days after the party, someone claims you are the father. Even if you are a woman. Cause fantasy setting, that's why.
9. You are mistaken for someone else, and charged with their tab. Pay 30% more money (no xp for it) or wake up in the slammer.
10. You expose one of your important guests as a reptilian! Have a fight with our scaly secret masters.
11. You are inducted into a cult. It takes your friends a week to deprogram you. -10% XP from this leveling action.
12. You wake up in stocks. -1 luck. Authorities let you out after a day.
13. You were robbed whilst unawares. Was it that saucy wench that you swear came to your room? You lose everything of value that you are carrying.
14. You break some knuckles punching a dude. No two-handed weapons/shields for 6 weeks.
15. Nobody comes to your party. -1 personality/charisma until you throw at least 500 gold into one party.
16. You are challenged to a duel, but cannot remember with who. At the most inconvenient time they show up.
17. If you are a halfling or a dwarf, you are tossed (if not, reroll). -3 Intelligence from hitting your head. +1 Charisma.
18. Your boasts have gotten you into trouble. You can't gain experience until you do something really awesome designated by the judge, like killing a legendary monster or stealing a legendary treasure.
19. You upset the mercantile guild. Everything is 20% more expensive for you and your associates in this town, unless you go to the black market, where things are 10% cheaper.
20. An evil magic user has some of your hair and flesh... you wake up with a gash and covered in strange runes.
21. It would seem that whenever someone says the words "my, its drafty in here" you feel the urge to do something embarrassing...
If you role a natural 20 on your Carouse check, you gain double experience and a luck point, then check for results in this column.
1. Gain a reputation as the life of the party. You will be invited to a fancy one soon.
2. Humiliate that one jerk/bitch you hate. Gain one to your luck or charisma.
3. Get on the good side of the local government representative. They will help you out when you need them.
4. Someone dies from too much partying at your party. Pity, but you are offered their job!
5. A comely lass or lad falls for you.
6. One of your guests is actually a supernatural entity that wants to be your bud, familiar or patron.
7. Your body adapts to all the partying. You get +1 to stamina checks versus alcohol and poisons until you fail a carousing check.
8. You run into a long-lost relative. Maybe they want to go adventuring with you?! (henchman)
9. You win a bar bet and gain the services of two henchmen with low morale for a month. They may stay on if you pay them.
10. You gain 3 rumors about the next adventure.
11. You are mistaken for an important figure and the party gets really going. +25% experience.
12. You make buds with a master and get a free training session worth 300 gold (roll on the martial training luck table now!).
13. The drunken friar joins your party! Get a friar as a NPC companion till he loses a morale save or you carouse again.
14. You totally see through Sir Bearington's disguise, but are cool about it, and he will show up when you need him most.
15. You gain a jester minion. He constantly grabs treasure from others (not you). You like him, but others may not...
16. You have a good gambling session. Get some booty and +1 luck. Your game judge determines the booty by their own system.
17. You judge some kind of bar event, and everyone praises your decisions! Gain +1 Personality.
18. You wake up next to a master spy that night. They mumble state secrets in their sleep that could be very lucrative for you.
19. You have an enlightening jape with some amazing adventurer! It nets you knowledge that gives you the saves (if better), hit die, or basic abilities of a random class different to your own.
20. Wake up with a random wand, potion, or magical version of a weapon from the weapons table.