Eat at the Varsity. The food may be greasy greaseballs of grease, but you still have to eat there.
Do the Dawg Walk. I regret that I did not do the Dawg Walk until after I graduated, but it's pretty incredible.
Walk the Classic City. Just take a long walk of a Sunday, downtown on Broad Street and the like. The shops there are fantastic, and the ambience is second to none.
Eat at Transmetropolitan. Seriously. GOOD good food.
See a show in the Cellar Theatre in the Fine Arts Building. It's the most intimate place in Athens that you can see a play, and it's a very good department (hey, they gave me a Master's degree!)
Visit the Butts-Mehre Building. Make an afternoon of it. Nothing in the world like seeing Frankie Sinkwich's Heisman...
It's happened to me, and it can actually be a great experience: spend a Saturday when you DON'T have a ticket to a football game on-campus, just listening to Larry on the radio and tailgating with friends. The feeling of hearing Larry call something over the airwaves and hearing the roar of the crowd from Sanford is chill-inducing.
Do SOMETHING organized on Herty Field. I don't care if it's flag football or study group or (like me) a series of environmental theatre pieces. Herty is wonderful.
Walk Sanford Street and smoke a fine cigar. Doesn't have to be gameday. It just has to be Sanford Street, and the bridge. You can buy your cigar at Trippi's, on the corner of Lexington and Gaines School, or at the Smoker's Den across from City Hall. I prefer Trippi's, myself.
Ride the campus bus. You meet people, and conversations are friendly on the campus bus where they would be creepy on public transit.
See a baseball game.
See a gym meet (I still haven't done this...)
Attend graduation.
And finally...
At least once while you're there, you need to flip off, boo or otherwise publicly deride Michael Adams. At least once. It's become a tradition, especially at Homecoming.
Red and Black, Win or Lose