Good decision getting an internship in Denver. There are tons of bars in LoDo for the younger crowd/hookup scene. There are also several good ones on 14th and 15th streets, around Blake/Market/Larimer.
Rio and D'Corazon are across the street. Both have very good Mexican food, but D'Corazon is a little better (known for their pork carnitas). The margaritas at Rio are amazing.
Great Divide Brewery tasting room (Arapahoe and 22nd) is awesome. Some of the best beer in the world, a nice crowd, and good pizza truck out front.
Snooze AM for breakfast- amazing pancakes. It's in one of the few shady spots in Denver, but you should be fine to walk during the day.
There are tons of good restaurants here, but not too many places that I crave (like I used to in Houston)... which is probably a good thing for me because I like to eat.
Burgers: City Grille on Colfax, Cherry Cricket in Cherry Creek, H-Burger on 16th, and Park Burger (never been there, but heard good things). Also, My Brother's Bar has good burgers and cool atmosphere.