Pacman for Excel 97 and 2000
Bob Gortician writes "From Usenet: A Japanese geek programmed a complete Pacman game running on Excel. It can approach the SNES in the future, and currently can run at
least MSX (Colecovision) games completely." The page is mostly in Japanese, but there's enough English to get one started. After careful consideration, I'm prepared to call this even cooler than the Flight Simulator in Excel. Excel might not be anyone's first choice for gaming platform, but it's helpful for anyone stuck in an office environment.
Considering more /.ers speak English than Japanese, the English version might be more useful.
One implementation, and other programs, can be found on this page