Re: Techniques for Demonstration
Having small people throw big people is a great crowd-pleaser. If you have some senior kid students they will doubtless be happy to oblige, or you can pair up adults of different sizes.
I like to see demonstrations with weapons, but bokken and jo are rather exotic to many spectators--tanto or short baton seem more "real" to them. Ki Society has a taigi form which shows six defenses against tanto attacks in a sort of escalation ("Oh, you're attacking again? Well, how about *this*?") and works nicely at demos.
When we do kids' demos we show a bit of what a class is like, not just flashy stuff but solo exercises and the early steps of learning a throw--kids' demos are for prospective parents and kids, and we want them to see the broad picture. We also do human pyramids, just because everyone seems to like this (except assistant instructors like me, who end up on the bottom with all those sharp little knees digging into our kidneys....)
Something to bear in mind is that demos have the same adrenaline factor as tests, and if you do challenging techniques there is an increased risk of injury. It's best to pick material that is very familiar and solid, even if it is not quite the flashiest. Also, even if you practice in advance, people may forget the plan and get confused--it's just stage fright. Give the main organizer a written cheat sheet just in case.