If you're hankering for some good ol', family friendly, cheap entertainment, I've got a solution for you. Go local and find a small-town Texas festival near you. I've been looking forward to a festival later this month in Georgetown since I missed last year's fest.
Poteet Strawberry Festival. There is an official judge of Poteet's best strawberries, a parade, carnival, and Taste of Texas Foodshow.
Bluebonnet Festival in Burnet. I attended this fest several years ago when a last minute cold snap rendered my cute spring shorts and sandals completely pointless. The shops around the Burnet courthouse were still fun to check out though. And bonus, if you live in the Austin area, you can ride the Austin steam train from Cedar Park to the festival in Burnet for an extra treat.
To find more festivals near you, check out this website: texasfairsandfestivals.com.