On of the guys in our club came up with a proposal for our indoor flying season. We typically fly once a month in the winter at a local church's gym.
His idea is to build and fly tow-line launched, micro sailplanes indoors. It sounds like a hoot to me!
Initially, a couple of the guys wanted to limit the wing span to 18". Then they upped it to 24". However, I pointed out that making things smaller is exactly the opposite of what you want to do if you want slow flight.
For sailplanes especially, wing span is your best friend. Wing loading is a distant second but still important. Its also much easier to get the span loading down if you build larger rather than smaller. Below a certain size, you start to need super light weight gear to make it workable. Ive found its much easier (and cheaper!) to use normal micro sized radio gear and put it in a larger foam model with as few weighty items as possible.
For launching, the options discussed were rubber band bungie, micro winch, something like the OneWinch and just pulling the string by hand as in towed launching. I thiink it would be a hoot to try to tow one up using another indoor model - like a Vapor
My plan at the moment is to shoot for something in the 60" to 79" range as far as span. It will have an under-cambered Depron wing with center dihedral and be RE only.
Even if it turns into a crash-n-burn session, it should be a hoot!