I have the Canon A610 with an u/w housing, it has a video mode on it so I can actually shoot a little video if I want (I've taken hundreds of u/w pictures but no video yet). I'm not sure what the options are for camcorders. I don't know if there are any that are waterproof but I bet there are waterproof bags that you can get for camcorders.
And by the way, it's not a stupid question at all!! Underwater photography has come a long ways thanks to housings and waterproof cameras, it's only logical that people would want to shoot video. I saw an amazing video online last year of a sea turtle that a diver was following but I don't remember what he was using for equipment, I'm pretty sure it was just a p&s camera with a housing.