Tired of sexed-up, "cute," and endless princesses and rainbow fairies marketed to your daughters on Halloween?
A Mighty Girl has put together a great collection of awesome costumes.
My three year old is super- psyched to be Batgirl. We actually own this, but I bought a new one because ours is worn, ripped, and missing parts.
(Of course, potential Batgirl enthusiasts would be helped along if there were multiple Batgirl movies and derivative toys, games, and clothing.