I'm in stitches at some of these! Some that I can still (unfortunately) remember...
Went out on the piss with friend, who was going out with my then boyfriend's best mate, who he also shared a house with. We became spectacularly plastered and on the way back to our boyfriends' house, somehow picked up a very creepy bloke who followed us into the house. Friend became scared when he wouldn't leave and woke up our BFs to get them to help. They found creepy bloke trying to get off with me, whilst I was throwing up in the loo... Apparently he DID NOT want to leave and was convinced he was on a promise. BF was none too happy with me in the morning!
Came home after a heavy night, got into bed with above boyfriend and promptly threw up everywhere. Woke up very confused as to why I was lying on a damp, bare mattress with no duvet and no boyfriend.
Had a one night stand with a man dressed as a Christmas tree. He even had a star on his head and baubles dangling from his ears. I seem to remember giggling to myself at my 'hilarious' chat up line 'Oooh can I feel your balls? They're so shiny and smooooth!' 
Became strangely obsessed whilst drunk with the fact that a friend always had a builder's bum and discovered that her arse crack started far further up her bum than mine. Compared arse cracks with several other friends and marvelled at how different they all were. Posed for a photo with friends, displaying our arse cracks in height order.