Hey group.
I definately think the umbrella might work. I get what you were saying about needing to secure it but maybe if it was taped down with some good old duct tape and secured to something stable like a chair, it might work. The wind action caused by it opening might have an effect on it too but hopefully not a big one. Maybe we could use it as a step if we dont like the final project. Like the wind from the umbrella opening then pushes something else.
Also, the setting off the mouse trap game might work but we would have to have something that winds up the trap which is hard to do.
Someone mentioned the idea of picking up a pen using a magnet which is a pretty good idea, i think. Because magnets are cheap as hell and grabbing a pen or something else thats metal might be cool.