Coffee continues to be the most efficient fuel for the human body's complex system of fuel injectors, auxiliary hearts, and flux capacitors. Fill up your flesh tank with today's Groupon: for $20, you get a two-hour Coffee 101 tour, a roasting demo, and a sampling lab at Batdorf & Bronson Coffee Roasters' Atlanta roastery on Carroll Drive.

Batdorf & Bronson Coffee Roasters roasts more than 20 premium coffees, benevolently sharing the secrets of a superb cup during the Coffee 101 tour. The two-hour trip fills heads with factoids on coffee's history, geographical spread, and how taste translates across areas. Eager eyeballs get a tour of the roastery, including a demo of how to craft flavorful at-home brews without having to bribe the coffee beans. The tour also includes several samples of Batdorf & Bronson's best blends, with possible tastes including the chocolaty Nicaragua Isabelia and the blueberry-hinted Ethiopia Yirgacheffe. Along with trivia tidbits, caffeinated Joes and Janes can walk out with a mug and a quarter-pound of their favorite blend.