What to shoot in Austin, Texas?

Hello Austinites,

I will be traveling to your fine city for business.  I've never been there before.  I'm going to have a day off in the middle of the week and thought I would do some walk-about photography downtown.  I'm interested  in architecture, landscapes, parks,  landmarks, that kind of thing.   I'll be staying downtown by the entertainment district.  Anything I should put in my 'can't miss' list?

Thanks,

Fritz