As the meme has grown over on, many posters have adopted avatars that featured the Go Play symbol in them. Thomas T. has been particularly prolific in his Go Play designs - here are most of the icons from that thread (till now):

Go Play Iwo JimaGo Play DicePause PlaySuperman Go PlayGo Play Green ArrowGo Play in Traffic

Edit: No way is this post gonna manage to keep up with gamer innovation, but here are a few more Icons: