We've been members of Space Center Houston for the past couple of years. We bought their friends & family package which includes unlimited admission for up to 6 (plus free parking) for a year, plus 2 guest passes. It is nice because we are only 10 minutes away so we can just go for a short while and not feel like we have to do everything. There are other benefits too such as not having to wait in lines and special events early admission.
This past Saturday, we did the tour of Mission Control. Be advised, you have to get advance tickets for this. They don't cost anything, but there's only a certain number of people who can get into the room and the whole thing takes about an hour by the time you load the tram, go to the building, get upstairs (you have to climb 87 steps or they do have an elevator), watch the presentation, take pictures, and return. We got there at opening at 9am. We got on the first tour which was at 9:30am. If you come later, you are likely to not be able to do the tour and you cannot do advance reservations.
For the 50th anniversary of the first Moon Landing, they completed restored Mission Control back to the way it looked in July 1969. The presentation is stunning and makes you feel like you are right there.
I highly recommend this!