A few of the ideas: Wear a white chef's hat and apron, and carry an iron (real or toy). What are you? An iron chef.

Tape a $1 bill to each ear to be a buccaneer.

On a black T-shirt and pants, make a line of dashes with white duct tape, starting at a bottom pant leg and ending at the shirt neckline, to simulate highway-lane dividing lines. Fasten a plastic fork across the dashes on the shirt to be a "fork in the road."