Musical chairs with Alice and the Mad Hatter! Ask the piano player at Coke Corner what time they're happening that day, since it's usually not published in any of the entertainment guides.
I'm stealing some of these - what a great list! Are you staying on property? My kids really enjoyed the scavenger hunts they give you at the front desk. We all had fun with them and learned a bunch too!
I forgot about the sword in the stone in front of the King Arthur's Carousel. I've heard that occasionally someone can actually pull it out! It's worth a good tug to find out