You can take things like old calculators, phones, etc. Remove the batteries and make sure there is no power source that can be plugged in when you aren't looking,grin, and let them take it apart.
We were at a kid's science function and they had a whole table just full of stuff that kids could take apart and look inside.

In fact, someone had actually bought a whole bunch of corded phones like we used to have back in the 70's grin brand new just to have kids take them apart to see what's inside.

Last edited by incogneato; 09/13/08 12:30 PM. Reason: smile didn't work