Lady Godiva is usually an eye-catcher

if you have enough courage to pull it off. (pun intended)
and while a total lack of
any costume would be the easiest way to do it, somehow I don't think the judge would be impressed.
Get a flesh-colored set of tights and sew on some felt or sequined fig leaves in the apropriate places, and get a long-hair wig. Short white gloves and slippers work well to hide the ends of the tights. A little extra padding in a few spots (sometimes a humorously large amount of extra padding works, if you are brave enough) will give the costume that little bit that makes the diference.
good luck with your show!