If you're holding too much weight, 24 Hour Fitness Worldwide can help you let go of some it. The company owns and operates about 425 fitness centers that offer aerobic, cardiovascular, and weight lifting activities to the chain's more than 4 million members. Some 24 Hour Fitness facilities also feature squash, racquetball, and basketball courts; swimming pools; steam and sauna rooms; tanning rooms; and whirlpools. It is one of the only fitness chains open 24 hours a day. Forstmann Little & Co owns 24 Hour Fitness, which was founded in 1983.