Most precious game in your collection?

I still have a soft spot for Zork. I love those old games. I guess it's the time they were made that I miss the most. I think I still have the last three Zorks made. Maybe some day I'll dust them off the give them a play

Many moons ago, I bought one or two of the Zork Anthology packs, collections of all their old games on one cd-rom. To be sure, nothing close to owning the original game with all the feelies and extras included. I have played a few text adventures before but was never good at figuring out what the game parser wanted of me.