Haven't had too many on a road bike, only one comes to mind.

Was riding home from work one night (about 17 years ago) and a car decided to pace me the rest of the way home (about 5 miles). Pulled up to the front step and was so exausted that I forgot to release my straps (105 clip pedals with cleats) and fell over right in front of them. Impressive pace but the dismount left some to be desired.

Mountain biking..coming down the trail after it had just rained heavily, saw two hikers coming up and moved over to make room, only to sink the front wheel in the mud and do 3/4s of a front flip. Came to a stop sitting on the ground with both feet still clipped in, still holding the handle bars and the bike sitting vertical on the rear tire between my legs and still managed to put a nice gash in my knee.

Riding with friends, showing off doing a wheelie and looped it straight on to my arse (I was clipped in). Never knew the ground could be so hard. Had to go to the movies that night with a donut pillow for my aching arse Boy did I catch a lot of flack for that one!