Most of the stuff I don't remember, my friends won't tell me about (unless it was really really good)... so I don't feel bad about it at all....
some of them from back in the day:
-one time I started speaking in Navajo or something
-walking up to random chicks, telling them "I want to jump their shit" and going home with them (this was a regular occurance)
-making embarrassing comments (too many to remember)
-doing just about anything to freak random people out
-tearing off my shirt after puking all over myself at a concert....
I know there are a lot more...
mine are not that bad though, I have a friend who turned into a dog once, (dog boy) was barking and clawing at some guys door we know... the guy opened the door and hit my buddy full swing in the forehead with a 5 wood...my buddy took off, actually yelping the whole way.... he also turned into spiderboy, insect boy, and various other animals (shark boy was great- he ran around the party and bit chicks in the ass)
luckily the details are hazy to most of these, or I might worry about it....