One of those nifty ideas in which I wish I could implement but can't due to lack of technical skill is that of interactive fiction. I could do a choose-your-own-adventure type thing, but that would take quite a bit of planning.
Before stumbling onto Nano, I had the idea of writing some hypertext fiction where clicking on links in the text would lead the reader on particular paths. I don't know whether or not I want to try this again. Maybe. But November is quite a ways off and then there's Script Frenzy. I could possibly modify the idea to fit the format of a script--with audience participation. Hm.