Yes, I know: Sudden Motion Sensor hacks are passé. But I finally got around to playing with one that invokes Exposé, and now I’m hooked. I ended up modifying it to invoke Dashboard instead, which required changing the script to call key code 111 for the F12 key.
So what does this do? Basically, if I want to see my Dashboard–which has weather and a couple other useful things on it, as well as some truly useless ones–I just tap the side of my laptop. Another tap dismisses it. Like I said: useless. (But very, very fun.)