Hi, it really depends on if you are bringing your family or flying solo. Additionally it would depend on your budget. The family would enjoy the Orlando Science center(its an interactive, educational, with cool sciency exhibits) but it is a little drive away from the tourist corridor just outside of downtown. Additionally you can try the The Ripleys museum which is very close to the convention center. AS someone suggested above the Kennedy space center is a must see. It is about a 45 minute drive from international drive. Gatorland is cool too but it is more of a zoo experience but they did just install some zip lines. Avoid orange blossom trail after dark unless you desire intimate companionship from individuals who may or may not be of the female gender and by all means no matter what anyone says. DO NOT go to the parliament house to unwind, take in a show, have a drink, spend the night, or relax , unless you like lots and lots of sausage.
Gl and have fun
dave