Hot Air Balloon Ride
Airboat Ride at Boggy Creek
Mini Golf - Pirates Cove on I Drive/Crossroads LBV or either of the two Disney courses
Baseball at Tampa Bay Devil Rays (or closer to Orlando, Lakeland Tigers(?) minor league)
Clearwater or St Petes Beach
Clearwater Sea Screamer boat trip to see dolphins
Day trip to St Augustine
Kennedy Space Centre (out of this world attraction, should be top of any list really)

Just a few to help you, I'm sure there will be further recommendations as well.

Something different would be to go to an Orlando Magic basketball match (unless you've been before). Even if you don't like basketball or understand the rules, it's a fun night out with lots of entertainment!

You can get tickets on ticketmaster.co.uk