There are tons of fun things to do and see in Texas. I have lived here for 10 years and these are some of the best:
SXSW, South By Southwest Media Conference
BBQ
Tex-Mex
The Alamo
Route 66
Sixth Floor Museum in Dallas
Bats in Austin
Caves in Georgetown and San Antonio
Rodeo
River Walk in San Antonio
Bluebonnet wildflowers in the Hill Country
Live Music in Austin
Houston Museum of Natural Science
Dallas Museum of Art
Paddle Boarding
State Fair of Texas
Houston Space Center