In the 70's a friend of a friend of mine developed Adventure which I'm sure you all know as the original text adventure game. It was a giant step in computer games. I worked at HP and someone ported it to the HP minicomputer. It got so popular they had to run a script to block it during work hours.

My wife and I came in every night after dinner for weeks and played it. When we weren't playing it we discussed ideas to get past the block. The word play was awesome.