Joel have you visited:
http://www.veggieprideparade.org/dept/contests.htm

The last one:
    * The best-using-the-least costume. (Is it simple but effective?)

This category seems right up your alley.

You may not have much time on your hands .... But do you have time to think...  that is, think something up?   ...perhaps in those wee small hours on some Sunday morn. in the near future.

Following is just a copy-and-paste from above URL.

The Veggie Pride Parade will sponsor a POSTER CONTEST with great prizes in the following categories:

    * Best poster, environment theme
    * Best poster, health theme
    * Best poster, social-issues theme
    * Best poster, bacterial-contamination theme
    * Best poster, manure theme
    * Best poster, ethical theme
    * Best poster, anti-factory-farming theme

The Veggie Pride Parade will sponsor a COSTUME CONTEST with great prizes in the following categories:

    * Most colorful costume.
    * Most-things-hanging-off-it costume.
    * Best vegetable costume.
    * Best fruit costume.
    * Most imaginative costume.
    * Most convincing costume—enough to make the meat eaters go veg!
    * Best edible costume.
    * The best-using-the-least costume. (Is it simple but effective?)

You should go as a flame! Wear red and orange, and paint your body and face in flames. If you want something a little more standard, you could be The Little Mermaid, a clown or a devil.