This isn't strictly about wanting to play a certain game, but it's definitely about wanting to play an adventure game cooperatively, so this seems to be the right forum.
Heard about Zinc? This freeware multiplayer IF interpreter is simply put a revolution for cooperative playing of text adventures. Check this out:
All who want to participate download the latest version of Zinc. The one who intends to act as server downloads the gamefile too. The server adds the game to Zinc's game list and starts it in server mode. All others start Zinc and connect to the server. You can chat while playing, as well as draw a map cooperatively, and anyone can type in commands (if the server is set to allow it).
Please note that the games that Zinc can play only support single-player, so while you all share playing the game, you won't have a character each in the game to play around with - you cooperatively work out what a single character should do.
Anyway, short of having a bunch of IF interested friends over at your house, I can't think of a better way to enjoy an IF game.
Zinc is written in Java and runs on all modern platforms. It can run games in Zcode and TADS format, as well as some Magnetic Scrolls games. I've tried playing Zcode and TADS games and it works very well. I have no connection to the product except for being a fan. It's freeware anyway, but I realise my enthusiasm could be mistaken for some kind of sales promotion.
If anyone with a public IP address would care to host a Zinc session some evening (European time), I'd like to join. Just mail me or MSN me at fredrik-xyzzy-ramsberg.net (replace -xyzzy- with @).