Is it a game? Well, you can move ponies around on the screen - good enough for me. PonyPlace is a simple yet elegant idea - a 2d pony chatroom with a wide variety of swappable avatars derived from the Desktop Ponies sprites. There were plenty of people online both times I logged on, although the project's still pretty basic - ideally, we'll see some more features in the future. Go check it out!
Update: Issue resolved, ponyplace is up and running again.
Update: Issue resolved, ponyplace is up and running again.