I had some friends that unscrewed kingdom melodies tapes (this was in the 80s) took out the contents and replaced it with rock. so if you looked at the tape collection in their car they looked like they only ever listened to kingdom melodies. Wankers.
I personally used to get semi drunk before conventions, leave my sunnies on all day and snooze. Or steal my mates keys from their meeting bag and take their car for a joy ride around the city during the sessions, returning it safely just in time. If you were lucky you could even put it back in the same car spot.
Oh i used to write cryptic names on my lapel badge instead of my own, that if you said quick enough said something stupid.
I wass sooooo bored.