Tex-Mex...go to Chuys!
Near campus...Hyde Park Bar & Grill (get the fries!), Kerby Lane Cafe (pancakes!)
BBQ...Green Mesquite, County Line
Burgers...Huts on 6th street
Try to visit the Whole Foods Market on 6th street (corporate hq)
Waterloo CD's is uniquely Austin
There are some great establishments on south Congress and South Lamar.
Barton Springs Pool...go to the south side to interact with the regular topless sunbathers
I'm sure others will contribute...