It'd be great if we could get enough people together to play a game of speed mafia at some point. If you're interested, stick your nick in the topic in #mafia.
There's some nice descriptions on MafiaScum's wiki, including a Newbie Guide.
If you're too lazy to click those links, it's basically a short role-playing game, with two sides; good (town) and evil (mafia), ideally played with around 8-10 players.
Speed Mafia is a deviant of Mafia played in real time (using IRC or MUDs), meaning the games last an hour or so, as apposed to a week or so.
Nor does anyone else, put your name on the list, it's relatively easy to pick up. Preferably mark yourself if you have played before... having a few people who've played before can make the game more interesting; they don't have any clear advantage.
There's a quick, ugly guide to playing that I wrote just before the first game. Get in contact if you want to change anything.
There are some logs of old Speed Mafia games played on the Discworld MUD avaliable at Tiggum's Mafia site. Warning: Not designed to be viewed by outsiders, beware of inside jokes and people with 'bad taste'.
Now games have actually happened, we have some of our own logged games.
http://scene.pgpl.net runs forum games, and has other mafia information.