If you really want something without batteries, then I'd go with a pinhole or a Holga (or something similar). That would limit the number of participants though, unless we did something different concerning the film. It would be different though, than what we've done before.
I don't want to be the source of any difficulties, but no matter what, even though I can receive a camera with batteries, I cannot send one, even with LR44 type. I don't know how, but Japan Post has a way of figuring out if there is ANY type of battery in a package - I've had more than one sent back to me (including for these exchanges). So, whoever comes after me has to be willing to get a new battery, unless I'm last.
Happy New Year everyone! I'm debating whether or not to brave the outdoors and go to a shrine for
hatsumode (the first shrine visit of the new year), but I think I'll finish off my umeshu (plum liqueur) and call it a night. Oh, and I could be wrong, but it seems to me I had the camera around this time last year.