Fort Worth (google it and see their website) is great with the Tarantula train and the cattle drive.

Just east is Arlington for Six FLags/Wet-n-Wild/Texas Rangers baseball

South on I-35W is Waco for Texas Ranger museum (not baseball, like Walker) and Cameron zoo.

Southwest of F/W is Dinosaur valley state park where you can walk in the footprints of the dinosaurs. There is a creation museum nearby as well.

Fossil Rim is near there where you can drive through while you are attacked by ostriches and other exotic African wildlife.