Meesh, this one happened today.
Head of NakamaCon, Eric Larson : Hey, we have no gaming room!  I should have planned this out weeks ago.  Could you set something up in a half hour?
Me:Sure thing!  *Brief internal panic over commitment to insane project.  Open mouth, insert foot.*
Eric:Thank you so much!  Glad to have the help.  Do you need any money?  
Me:No, that's fine.  I can cover it!  *Mmmm, tasty foot.*
At this point there is a Loony Tunes esque dash to the nearest board-gaming shop, and a 20 dollar purchase of the Munchkin card game with a bunch of dice.  This is followed by a crazy skidding stop back in the con hall and then 25 minutes worth of hurried sign-making and people gathering.
At last, a fully functional game of Munchkin that lasts for hours.
Eric:Oh awesome!  Hey, do you want to run the gaming room for the whole weekend?
Me: Definitely!  
*I am suddenly convinced my mouth has a mind of it's own and wishes to kill me.*