Some guy on The Awful Forums made a JavaScript clone of Windows Minesweeper a while back. It didn’t detect right-clicks properly and had some bugs in Safari, but I fixed it and made it into a widget (yet another instance of me standing on some else’s shoulders). Anyway anyone who wants it can click here.
Since the original Windows graphics are used, there’s probably some copyright infringement going on. Oh well, this screenshot makes it worth it.