My children enjoy watching episodes of The Wubbcast while waiting the doctor's office, the pizza place, etc. The Wubbcast plays fairly well in the standard media player, and I keep a selection of episodes on the SD cards in my N800.

EDIT: http://www.flickr.com/photos/sjgadsb...7601780004446/

Beyond that, first child is old enough to be minimally trusted handling the tablet, so he gets to draw pictures in Sketch. Also, all three children enjoy seeing quick photos and video clips of themselves taken on the spot. Megapixels don't seem to matter to the pre-school set, just so long as they're the stars on screen.

Heh. My wife considers anything computer-related "for my job" and encourages me to purchase whatever I feel I need. Luckily, I'm, err, thrifty.