Used to enjoy going to Fiesta Texas during the offseason. No lines and the workers were so damn stoned you could basically do anything. Had a season pass for awhile and was always getting cheap/free tickets. Got to be that you'd recognize the performers and go, "this is the third year in a row I've seen that blond sing boogie woogie santa claus for minimum wage..." Anyway, nice diversion for 2 or 3 hours and it was only about a 20 minute drive.
Sea World, though, meh. The last time I went, I got to listen to how killer whales have a range in nature of thousands of miles while I watched one swim around in circles in a tiny swimming pool. That was it for me. Blackfish is a great documentary if you like listening to crazy, attractive people talk.
Houston.. well... AstroWorld is now a parking lot for the Houston rodeo. And we've got some scammer that's been raising money for "Dinosaur Land" for at least 20 years.
EDIT: The dinosaur scam is still going....
http://www.earthquestadventures.com/