I'm not a fan of kids' toys designed to look like grown-ups' gadgets (e.g. kiddie cell phones, laptops, and ATMs), but I may have to make an exception here. The KidiDoodle is a mini drawing tablet and screen. Even cooler, they come two-to-a-package and they communicate with each other via IR, so you can "email" your drawing to your buddy.
I read about this in an EETimes article that describes their innards in detail (based on resistive touchpad technology): VTech's KidiDoodle: Touch-pad Technology Meets Child's Play.
I ordered a set for my nephews… unless I decide to keep them for, uh, research purposes.