If you've seen the movie Apollo 13, then you are familiar with this phrase! Houston is the home of NASA's Johnson Space Center and the infamous "mission control." I'm sure that there are other things that it is known for (hey - they even hosted the Super Bowl a few years ago), but that is the thing that I can think of off the top of my head.
My husband and I visited NASA's Space Center Houston a couple of years ago. It was a bit pricey (I think we paid about $25) and you can get discounts using a AAA card, a Southwest Airlines Rapid Rewards card, and local grocery stores often have coupons, as well. I think that families with young children (in the 5-11 year old range) would enjoy this experience most because there are a LOT of hands-on activities and exhibits for the kids. They can walk through a "mock" space shuttle among other things. Adults can do this, as well, but I don't think it has the same effect! You can take a "tour" of the facilities. I have taken this tour in the past and it has changed drastically and is very limited at this point. I am thinking that they had to change it quite a bit after the events on 9/11. You do get to see the mock International Space Station where actual astronauts train. You also get to visit the old mission control facilities (on the day we went, the elevators were out and we had to climb the stairs to the top!) and they show you a re-enactment. That was probably the "neatest" part for me. You also get to view a bunch of "retired" space shuttles. I think my husband really enjoyed that part. There are a videos about the history of the space program. There are plenty of gift shops, and of course, everything was overpriced (that's my opinion, at least). The food in the restaurants was also pricey.
Overall, it's an educational experience, but it's also a very expensive one, so come prepared to spend and spend! If you'd like to find out more Space Center Houston, you can visit their website here: http://www.spacecenter.org/