There's lots to do in Austin. Come a few days early or stay a few days late. Don't miss the conference, but check out some of these great things as well!
Austin is a foodie's paradise. You will be able to find many fantastic options around campus, near the hotel, and downtown (a reasonable walk or public transit ride from the venues). A good source of information is Austin's Eater page. Local faves are barbecue and tacos (including breakfast tacos), but you will easily find eclectic fare, and plenty of vegetarian and vegan options.
Austin is famous for live music, and you'll find plenty of it. There are lots of great (small) music venues. There are as many great lists for these, but here's a good one. If you're looking for information on the various nightlife districts in general, this page gives a good run down.