Mammoth exhibit is pretty sweet. The Texas Rangers Museum (not the baseball team) is very well done and is a 5 minute walk from the stadium.
For food there are several good places down town - Ninfa’s, Alpha Omega, and Clay Pot. Slow Rise on the Brazos is also fun in the evening. Jorge’s is a new place that is upscale Tex-Mex - split a meal. It’s too big for one person.
For BBQ there is Helberg’s, Vitek’s, and Guess Family.