Why not use a clapperboard with your home movies for that authentic film production! Lights, camera, action!

The definition of a clapperboard, according to Wikipedia, the free encyclopedia, is as follows:

'A clapperboard is a device used in the movie industry to synchronize sound and video. A typical clapperboard consists of a board or slate with a hinged piece of wood attached. Details of the shot being filmed are written on the board which is held in front of the camera at the beginning (or sometimes the end) of that shot. These details are also read aloud and then the clapper is literally clapped against the board. The frame at which the clapper closes can then be matched to the corresponding clap on the soundtrack, allowing the sound and picture to be synchronized for editing purposes.'