Bars in Dallas

Hi,
Visiting Dallas this week and was wondering what are some good bars to check out. Looking for casual bars to go with/without work associates. I heard you all have a few rooftop bars that are supposed to be cool. Can do with or without food. Not opposed to having some company either one of those days. I am staying in the downtown area. Might check out a baseball game and possibly a Mavs game so anything near there as well? Thanks for any help.