The Artist's Corner in the Penny Arcade forums has taken inspiration from the upcoming 'Blackest Night' comics event in Green Lantern, and is inviting people to invent their own characters using the Green Lantern color spectrum and post them to thread. Right now there's a lot of pictures of yaks with power rings? But it seems like a fun exercise with a lot of potential, and also has an informative rundown of all the Lanterns and their emotion powers if you need to play catchup.