Need something to demonstrate in 3 minutes
For a class I'm taking, I need to make a speech in 3 minutes that demonstrates how to do something. It could be something very simple, but being the person that I am I want it to be at least mildly impressive. My hunch was to do something computing related with my eeepc and a projector, but that idea got nixed. I'm also interested in electronics, though, and I have a lot of stuff in my junk box.
Anyway, I'm not asking anyone to do my work for me, this is more about presentation skills. But if you happen to have an idea of what I can do quickly and with minimal likelihood of failure I'd be eternally grateful.