I put together this little model kit today. It is actually a working twin lens reflex camera that shoots on 35mm film. It doesn't have a lot of controls, however the viewing lens and the shooting lens are linked, so you can actually focus via the viewfinder. It also has a removable aperture plate which allow you to change to a wider aperture if you want shorter depth of field. I'm going to put a roll of film in it right now and then develop it next week during my class's processing demonstration.
If you would like to get a camera like this, there are two possibilities; The Gakkenflex was included with issue 25 of Otona no Kagaku Magazine, a Japanese science publication that always comes with some kind of science kit. The other, cheaper option is to look for a Recesky kit, which is a clone of the Gakken camera. It doesn't come with the magazine (which you probably don't want anyway, unless you can read Japanese)and it has a few minor cosmetic changes. It's pretty much the same camera though. You should be able to find on on ebay for about $20 while the Gakken will probably be $50 or $60.