Invitation: Join one of our Challenge Groups: The…Invitation: Join one of our Challenge Groups: The post Invitation: Join one of our Challenge Groups appeared… bit.ly/1yHa5DlShare this:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to print (Opens in new window)Click to email a link to a friend (Opens in new window)