In Medias Res

Ever started a role-playing game in medias res ("in the middle of things")? You should. It makes for a refreshing change. The idea is to start a session off with an action set-piece or in the middle of a big twist, ignoring any kind of slow-paced introduction or set-up in favor of waking the players up right from the get go. It might not work for every campaign - some keep track of every waking moment and wouldn't allow for such a narrative jump - but here are a few examples:

In an espionage game, or any game that relies on "missions", go the James Bond route and start things off with a big stunt. It could be the end of the previous (untold) adventure, segueing into the new scenario. It might be the start of the mission, but with a dull mission briefing played via an envelope full of documents or a quick flashback after the action is over.

In epic poetry, in medias res is usually prelude to a long flashback as we go back to the beginning, and only then followed by the rest of the story. Games need never flash back at all - especially in cases where it would deflate the tension to know everyone was alive and well in the middle of the story - but you could fiendishly describe how things have changed, and force the players not only to play their characters through the various obstacles and twists of your story, but also to set themselves up for that "middle". Who is that dead body on the floor? Where's the team's van? Just how did your cyberdecker get painted blue? Players know they'll survive until the discovery of the dead body, but they must make sure to lose the van and drop a bucket of paint on a guy. So destiny dictates.

One version of this that works well, but is a bit of a cheat, is what I call "in amnesia res". In this scenario, you set up a middle situation as above, but the characters come into in not remembering how they got there. There is no flashback, only an investigation leading to their putting the pieces of the puzzle together. The space marines wake up from cryosleep to an empty ship and there's something there with them... or they've been surgically altered. That kind of thing. Memory loss spells, temporal distortions, etc.

One fair warning: While you're designing the middle situation for your players, make sure you never make a decision for any of them that they would never have taken themselves. A gambling addict might have to start a game naked in an alley, that's fine (and a good way to play up "disadvantages" the players took), but you can't start a game with a character on the run from the police because he just killed his wife (unless there's a major twist or you're playing something incredibly f***ed-up like Unknown Armies or Over the Edge). Maybe give the player a veto over any such thing, but that depends on how improvised or prepared your sessions are.

Where the adventure starts doesn't have to be at the start... Anyone else go by such a credo?