I've been personally wanting to try out this game when I first read about it 2 years ago. And then I recently read an RPS post that you can now sign up for the early access beta! Wait, what? Haven't heard of SpyParty? This video tutorial, produced by the one-man-band developer, Chris Hecker, shows the basics of the game mechanics:
If this game piques your interest, feel free to sign up for the beta. Please take note though: this is a paid beta. You of course get the whole game via Steam when it comes out, and also the latest build of the beta -- it seems there is a new update everyday. So be prepared to shell out $15 once your acceptance email arrives. More details on the pricing could be found here.
I regret signing up so late as the beta release is almost down to a trickle. As soon as I get my beta invite, I will post my impressions of the game. Hoping to play and outwit some OMGeeks if you do decide to sign up!