If your in the Houston area I would really encourage you to stop by and visit, is it a must see. For Houston I'd say, given the history. There are several different tram options to choose from (TIP: do your research prior to arriving and you will beat the rush), some included in your admission and others extra. Whatever you do, don't miss out on the team tour.
The interactive museum area is great for curious children and adults. It also serves as a great educational piece on the space program. You can easily spend a few hours or more (average 3 hours I'd say). Ticket prices were $29.00 for adults.