Javascript Game of Tron In 226 Bytes
Have you upgraded your hardware to play something beefier than 140-byte Tetris?
New submitter alokmenghrajani writes with "a detailed view of how we size-optimized a game of Tron to just 226 bytes." It's also optimized for Chrome, and very fast.
It works on chrome and firefox. This isn't a portability issue: normally developers add huge amounts of code to support IE. If it needs tweaking for IE, it would probably be 50% larger.