If 24-Hour Fitness kept charging even after you cancelled, you might be eligible to join a class action lawsuit against them. You can join if you were debited between Oct 2, 2002 and Feb 28, 2010. You could get $20 back, or, in a perhaps ironic twist, a three month gift certificate to 24-Hour Fitnesss.
Join The 24 Hour Fitness Class Action Lawsuit
By May 3, 2010