Riding a bike is an easy way to minimize your carbon footprint, like reusing plastic bags as wedding gifts. Make the world a better place with this Groupon.

$29 for Basic Bike Tune-Up ($60 Value)

During the basic tune-up, factory-trained technicians true wheels, inspect and calibrate brakes and gears, and lubricate drivetrains. They also wipe down cycles from handlebar to tire and check air pressure.

Carl Hart Bicycles

In 1913, German-born Carl Braunhart debuted a shop of high-quality cycles that eventually migrated stateside and, over the years, traded hands to his great-grandson. In 1980, Fred Feller bought the shop from the Braunhart family, and when his son, Darren, graduated from college, Carl Hart Bicycles once again became a multigenerational family business.

Today, Fred and Darren's staff of factory-certified technicians and cycling enthusiasts, some with backgrounds in semiprofessional racing, help patrons sift through an impressive inventory of quality bicycles from top industry brands such as Trek, Specialized, and Cannondale. Most two-wheelers come in five to eight sizes for myriad heights, and staffers measure customers to find the best fit. But when a traditional bicycle won't suffice, they send measurements to Seven Cycles or Guru factories, where workers craft customized frames. Custom-fit bikes contour to riders' bodies, cushioning the stress of frequent biking and the need to throw bikes at slow-moving pedestrians.

Before committing to any purchase, customers are encouraged to take a test spin around the parking lot or stop by on Demo Days. On these days, bike manufacturers bring their cycles to the store and patrons can try them on for size as they pop wheelies over unassuming companions or traverse miles of mountain trails that branch out from the shop. On Saturdays, Darren or an assistant manager takes groups of up to 35 cyclists on 36-mile excursions. Afterwards, athletes refuel with bagels at the shop.