Ha, when I opened this thread, I was all smug, thinking 'I've never done anything too bad, just the usual falling into / onto / over stuff'. Then it all came screaming back... Some of my, ahem, 'finest' moments:
Deciding to leave a friend's party at around 5am, instead of staying over, heading to the train station, sitting down to wait for my train, falling asleep on the bench, then being woken by a kindly lady who thought I was homeless (was in my scruffy 17 year old days). Running for my train, then falling asleep on it and waking up about 2 hours north of my stop, at the end of the line. Having to get back on the same train to get home, and then having to explain to the conductor why I didn't have the right ticket. The poor bloke didn't fine me, just looked at me with great pity and told me to go home to bed.
Shagging a bloke in a bunk on a tour bus, on which about 7 other blokes were trying to sleep.
Puking in DP's hood in a taxi.
Licking 
the face of a well known musician backstage at a gig in LA... Then queuing aaages for the (only) loo, opting to share it with some random woman who was queuing ahead of me, and then, when she was taking too long, peeing in the shower in this huge bathroom that was supposed to be for the band.
Running around a forest at a festival, at 7am, looking for toast (?), swinging from trees, and jumping out at random passers-by yelling 'boo!', in a hideous faux fur coat (and feck all else). Then insisting some strange boy go back to the campsite and buy me toast.
That's not even the half of it. . Am all well behaved and grown up now, I promise (mostly).