...or, how many abbreviations can I fit in the subject?

Seriously, I am thinking of running a one-shot tabletop RPG at Southern Exposure II. The question is, what should I run?

I can run IronClaw, but it will be the usual basic Intro Adventure my usual victims know and love.

I can run the new Usagi Yojimbo RPG, from the makers of IronClaw (and using a similar system).

I can run the World or Warcraft RPG, which is a d20 game.
Any game I run will be a one-shot, not a campaign or a seed for a campaign, as I can't commit to one at this time. But I'm curious as to which one people would be most interested in trying out.