I just checked and there are several games in progress as I type this.
Just go to the site, set up whatever kind of game options you want, and click the "offer game" button. Your game should show up on the "home" page and now all you have to do is wait for someone to take up your game.
If someone else already has a game offered that you want to try, accept the game and you should be off and running.
You can also click the green buttons on the right side of the player list to watch other games in progress.