A while ago I bought a fake Wii remote and nunchuck to play with (I don't actually own a Wii). My tri-wing screwdriver arrived a few days ago, and here's what their insides look like (you can contrast with the real thing) (click on a picture for higher resolution, and more pics):

It turns out the peripherals are easy to use with a microcontroller. Since the nunchucks can be had for under $6, its easily the cheapest way to add an accelerometer to a project. (Wireless ones are about $14.)