This is a multi-site, randomized controlled trial. Participants will be randomized into one of three conditions for six months: cybercycle-tour, cybercycle-game, or videogame alone. Comprehensive evaluations will include: neuropsychological (e.g., executive function and memory), behavioral (e.g., compliance and effort/watts), physiological (e.g., cardiorespiratory fitness), biomarker (e.g., BDNF), and an expanded neuroimaging pilot. After the six-month intervention period, participants choose whether or not to continue exercising, using any of the three conditions.