I'm attempting to do the Couch-to-5K (C25K) Running Plan with terrible knees, sooo... This is C25K with yoga and Pilates thrown in to help build strength and flexibility and (hopefully) prevent injury.
The C25K program can be found here:
http://www.coolrunning.com/engine/2/2_3/181.shtml
Join a team or create your own! There are lots of teams on Social Workout, and each gets its own page. A team can participate in
any challenge as long as at least one team member joins the challenge, and the challenge host adds the team to the challenge.