J.C.
I was Cleopatra this year. http://www.walmart.com/ip/Cleopatra-Adult-Costume/11539279. I paid $20 for the costume and now I see it is on sale for $15. Darn!!!
My 15 year old actually looked really cute with very little effort. She wore all black (tights, high boots, black sweater) and we bought cat ears, bow tie and tail at walmart for $5.
My mom wore all pink this year and bought the bunny ears bow tie and tail. Very cute. You can also draw whiskers out of eye liner.
Have fun!!