Underwater Moviemaking [Classic Retro Thing]
Thanks to computer-based editing, filmmaking is more popular today than it was ten years ago. To get you started, how about The Fujica AX100? It's a tiny Single-8 movie camera produced by Fuji in the early 1970s. It's easy to use, with an extremely fast F/1.1 lens for low-light shooting and one-button point-and-shoot filming. The AX100 uses Fuji Single-8 film cartridges, which are still available for $16 plus processing.
If you're really lucky, you might find one with the Fujica MarinePack 8 underwater housing (pictured after the jump). With its targeting sight, weird plastic fins, and suspicious looking lens holes, this is definitely not something to toss into your carry-on luggage.
The Fujica AX100 in its optional MarinePack underwater housing. When new, these were waterproof up to 40m (about 120ft). These days, I'd try it in the bathtub first. Perfect for re-enacting Jaws in your neighbor's pool.