Infocom offers free downloads of Zork I, II, and III for Windows or Mac. That's the best deal we've seen on these classic, text-based interactive fiction games that let you re-live the "good old days" when video games required a player to have good typing skills and an imagination.

Of note, the Mac version won't work natively on an Apple computer running OS X, as a Grue has eaten that bit of code.