Classic gaming!
Bethesda has just released the classic Wolfenstein 3D (the game that helped popularize the first-person shooter genre as well as starting iD Software on its path to becoming a household name in the 1990s) to play for free on the web, to mark the 20th anniversary of its release. Have fun!
(Oh, and if you're so inclined, don't forget you can also download the source code, although much of the original art and music remains under copyright.)
(Oh, and if you're so inclined, don't forget you can also download the source code, although much of the original art and music remains under copyright.)