1) Get a plain white t-shirt, and draw a big "euro" symbol on both sides of it. That way, when you get drunk at your Halloween party and have to collapse, you can go as "the collapse of the euro".
2) If you're a girl, wear plenty of makeup and then toss yourself down a flight of stairs. Now, you're Lindsay Lohan!
3) If you can't make it to the party, just tell everyone that you'll be showing up as "civility in politics". Then when you don't show up, they'll understand your point.
4) Wear a Sarah Palin mask and go as 2008.
5) Dress up as Amy Winehouse and go as "Too Soon."
6) Drink all the host's booze, grope several guests, and smash something, and tell everyone that you're going as yourself before rehab. Note--you might really want to go into rehab afterwards.
7) Dress like Richard Burton's character in "Who's Afraid of Virginia Woolf?" and then spend the rest of the evening explaining to people what you were going for and get pissed at them for not having any taste for the classics.
8) Attach containers of fish food to your sweater, and go as "Osama Bin Laden".
9) Go as an abstract concept such as "The Importance of Being Earnest" and then marvel at how many fewer friends you have by the enf of the evening.