Return to Zork: Another Story

In this game you play the classic game "Return to Zork", but not exactly. If you're unable to play Infocom's Return to ZORK, this is almost as good. The background story is in the slightly extensive documentation.
In fact, I actually liked this game more than the original Infocom one.
The game comes with background documentation, probably just to keep the Infocom feel alive. I _TOTALLY recommend this game, but not for beginners.