Hi
My son loved this game when he was 3.
http://www.fatbraintoys.com/toy_comp...ggy_boogie.cfm
Also, maybe a deck of large, strudy funny cards. We have this one with vegetable faces(I know, sounds weird), but you can play concentration with them. Matching pictures. We started with just a couple of pairs and built up to more pairs as he was able to handle them.
I love the backpack idea! And, the Leapster. I got one for my niece who just turned 3.