What's fun/interesting to do in Atlanta?

There's 5 of us guys aged 24-29 from Vancouver following the Vancouver Canucks on their road trip March 22-30. We're going to Detroit, Atlanta, Columbus, and Nashville. Other than the hockey game, we are looking for fun/cool things to do/sightsee when we come to Atlanta. Any suggestions? The closer to the city centre the better, but anything is helpful.