Just about everyone who's spent any time on the set of Foiled has had a go on the clapperboard. It comes in handy in two ways when I'm editing; first to give me a visual and auditory reference of the scene being shot, and secondly to provide a sync between the sound and picture (not really very relevant as I'm editing on video and they're linked anyway, but it could be handy if I start moving soundtracks around).
Here are just a few of the "claps":
The Holy Clapperman
Shaun Gostelow