They are having free outdoor concerts with Muse and other popular bands each day in Centennial Park. Check out concert line up on final four events website. Have a fan-fest also, but more family oriented.
Braves are playing the Cubs this weekend. I don't have final four tickets, but heading downtown on Saturday to bar hop and hang out with the hoops fans. Good sports bars downtown are Stats, Ted's Montana grill (if you like buffalo burgers) and Jocks and Jills. Good view of downtown skyline and Centennial park from the Glenn hotel rooftop bar. Many gay bars in midtown Atlanta. Have fun !