hey man. www.bikesbl.org has a ton of good rides depending on how fast you want to go.

if you're a racer, there is an airport ride on Sunday, and a ride in Tucker on Saturday for brisk base miles. There is a practice crit(very fast) in Marietta, but I'm not sure if it goes on during the winter. actually it looks like it doesn't

www.sadlebred.com has a lot of other great rides.

let me know what kind of rides you're looking for and I can help you out. Also what part of town?

edit: not sure about the bike rental...I think you can rent bikes at the silver comet depot on the silver comet. If you're an exceptionally tall guy, I may be able to hook you up with a bike.