Where to pick up coupons for Space Center

Wondering how you can afford to keep the kids entertained this summer?
A glimpse of Bail Organa's airspeeder and General Grievous' starfighter doesn't come all that cheap at Space Center Houston -- $15.95 for little kids and $19.95 for ages 12 and up -- but then, I've never understood why anyone would pay full price. Even to see the 40-foot-deep pool where the astronauts train for weightlessness.
Here's a list of Space Center partners that usually have half-off coupons around, at least if you visit locations near NASA.
McDonald's
Academy
Centerpoint Energy
CVS pharmacies
Hollywood Video
Game Crazy
IHOP
Kroger
Sam's Club
Subway
Wells Fargo
An even better bargain may be CityPass. For $39 per adult, $29 per child, you get a booklet of tickets to six Houston-area attractions over nine days:
Space Center Houston
Downtown Aquarium
Houston Museum of Natural Science
Houston Zoo
Choose between the Health Museum and George Ranch Historical Park
Choose between the Museum of Fine Arts Houston and the Children's Museum of Houston
You can buy a CityPass online.