Lots! Let's see.....
In Innoventions, they just opened an area where you can try out a segway for free. Apparantly, you only go down a small aisle and back, but it's still cool!
Also in Innoventions, check out the house of the future, it's kind of a short tour/presentation thing.
One more thing in Innoventions, go to the "Fantastic Plastic" section. First you learn how plastics are manufactured and used, then in teams, you build a virtual robot, and race it against everyone elses robot (with you running on a special mat to make the robot move) then finally you get to build your own FREE robot at the end and take it home.....really fun!
In the Land, you MUST check out Soarin, and I personally love Living with the Land. They also have a short tour for $12 called Behind the Seeds, which I plan to take when I go in two weeks, I let you know how it is.
Over at the Living Seas, Turtle Talk is another must see. Through computer animation and disney magic, Crush from Finding Nemo interacts with the audience.
I dont know if you plan on doing Mission Space, but you should definately check out the post-show area, where they have a play area, places where you can send video postcards for free via the internet, and play a multi-player Space Race game that's a lot of fun.
I hope that helps!