Carl's Gym is one of the older fitness centers in Millennium City.
Carl's Gym hearkens back to the days when a good fighter used a speed-bag instead of a submachine gun.
The gym survived the city-wide destruction during the Battle of Detroit and became one of the shelters for the homeless. City leaders fought hard to keep the gym intact during the transition into Millennium City, but it wasn't easy. The various criminal element make it difficult for Carl to bring in new members. But Carl has a soft spot for heroes, so he'll often arrange deals for heroes to use the facilities either at a reduced rate or sometimes for free.
Recently Carl allowed the sword-wielding hero Starlett to stay at the Gym for free provided she help with some of the maintenance after-hours. It also helped that she was able to give him a rare signed photo of Sapphire from her Key West photoshoot.
The gym's centerpiece is an old-fashioned boxing ring, which can be used for hand-to-hand fighting. It also has exercise equipment, treadmills, showers, saunas, and a separate social area for people to meet.
(Please see the gym's Champions Online Wiki entry for more information.)
Carl's Gym was seen in "Future's Guardian" #4.