Here's a great project idea, that requires a great deal of work, better to be undertaken as a team. Anyway something of this scale might be a little over kill for most of us, but perhaps something smaller on the same lines could still be quite impressive.
Take a look at the video below and leave some comments in the comments area. The only thing I really don't get about this video is that it shows you the preparation phase (like getting the magnet, getting the electronics inside the balls) but then is quite brief on showing the actual thing working. I would happily take a full 10 minutes or more just looking at the movement of the balls!
INDUCTANCE - Physalia from F5 on Vimeo.