It's a browser based game that's linked in to Twitter and Facebook, so I was initially skeptical of it, but it's turned out to be a whole lot of fun. In a way, it's a card game/RPG that's set in "Fallen London", a version of London that's sunk beneath the surface and is that much closer to hell. It's got a very Victorian tilt to it, and has reminded a few of us of Neverwhere (by Neil Gaiman) already.
I think the beauty of the game is in the storytelling. You're given a lot of choice for where you want to explore and what kind of abilities/contacts you want to pursue, but they're all a little bit dangerous and quirky. At the moment, I've been having terrible nightmares . . . reoccurring dreams that culminated in my character going completely insane . . . Right now I'm lost in a strange world of insanity. And in the outside world, my nemesis has appeared somewhere and the remembered death of an old love is driving me to revenge!
Well worth checking out . . . there's a side of the game that involves getting more actions by posting tidbits from it on facebook or twitter, which is a little bit annoying, but I haven't done any of that yet (maybe I will after this post just to show it). There's some limited interaction with facebook/twitter friends also.