This year, I'm totally at a loss.
I think my brand of creativity is pretty weak in terms of thinking up a new idea by myself; on the other hand, I find that it's really easy for me to determine how practicable an existing idea would be, or to think up variations to an existing idea. For example, last year's Van Gogh costume started with the theme of "your favorite dead person" (from a party we'd been invited to) and I started thinking of artists whose work I like, and then how cool it would be if I could go as how an artist saw himself. Bam, there it was.
Once I'd settled on it, I really enjoyed thinking it through and doing it, and I was happy with the results. So I'd like to find an idea with that kind of potential again, and make it work.
(PS: No, Betsy, I'm not going to go as the South Tower. Sicko.)