Now through September 1st, teenagers ages 15 to 18 can sign up for a free membership at Planet Fitness allowing them to work out all summer long. Teens under 18 must bring a parent or guardian to sign up at Planet Fitness. Teens can work out alone as much as they want from now through September 1st. All teens who sign up for the Teen Summer Challenge are also automatically entered into the Planet Fitness’ Scholarship Sweepstakes. One teen from each of the 50 states will be chosen to win a $500 scholarship, with one lucky teen winning a $5,000 grand prize.