23rd Oct: It's time for the second TV Tropes Halloween Avatar Contest, theme: cute monsters! Details and voting here.
BYOND (Build Your Own Net Dream) is a free Game Engine / Game Maker for 2D tile-based multiplayer games. It was originally created to make MUDs, but eventually grew to include graphics. While it's not that popular on the broader internet, several individual games are.
Notable BYOND Games: