big hairy one-act play challenge

I have the next two weeks off work, from Monday Dec 18 all the way to January 1st. During that time I'd like to write a one-act play, but I have no idea as to setting, premise, characters, anything. My only rule is that they have to be able to speak - otherwise the possibilities for dialogue start evaporating. Scratch that - a bunch of mute characters might be interesting as well.

What I need from you folk is suggestions - give me the rules for the play I'm going to write. Starting Monday, I have two weeks to come up with a rough draft. I'll take the most workable and wacky ideas you've got and grind them all into a paste of high art.

I have some faithful commenters on this site and a whole lotta lurkers. De-lurk for me this one time for a collaborative effort at playwrightness. Remember that I am very fond of certain themes - time travel, zombies, robots, the Irish, the Aral Sea, and post-apocalyptic wastelands - but don't let that limit you. I look forward to your suggestions, from the idle to the inspired.

Go!