I went specifically to see the Dead Sea Scrolls which was a temporary exhibition between October 2004 and January 2005. It was excellent - really well presented!
At the same time there was also an exhitbition on Tibetan Treasures. I didn't see this exhibition however I heard it was equally as good.
The Houston Museum of Natural Science is at the edge of Hermann Park and within the Museum district of Houston. If you're in Houston for business or pleasure - this is one of the areas to get to first.
Check out the website link as well - excellent!
Prices: $6 for adult general admission
Special exhibitions may be extra.

