I think the butterfly center at the Houston Museum of Natural Science is one of the hidden gems in this city.  Yes, they have tried to sex it up a little bit for the kids with bug exhibits that the kids will find wonderously disgusting while creeping out their parents, but if you walk past that and into the simulated rain forest you’ll be transported into a little spot of zen inside of Houston. Turn off your cell phone, listen to the waterfall, and enjoy the butterflies.  It’s great on your lunch hour.  Tip: buy your tickets at the gift shop to avoid the lines when there’s a popular exhibit elsewhere in the museum.