Bubblefishymon. Not a game, but it gives funny but very functional visual appearance to system/memory load, which helps a lot to get the system status. I think discovered it in the late 90s or early 2k as a couple Windowmaker dockapps which later merged into a single one which was also ported to Gkrellm, and still use it under Xfce. http://pigeond.net/bfm/