FAMILY GUY Season 6 Episode 3 : Believe it or Not, Joe's Walking on Air

When Joe feels that his disability is holding Bonnie back from living a full life, he decides to get a leg transplant. Excited about his new ability to walk, Joe engages in extreme sports, and soon ditches his current friends, for more active ones. Peter and the guys are upset at how Joe is acting and decide to teach him a lesson.