(The name, Take Back Halloween!, refers to the current trend for women's Halloween costumes to be a "sexy" version of some generic category or character: I've blogged before about unimaginatively "sexy" superhero costumes. The ladies at Take Back Halloween! want to see more thoughtful, creative, personalized Halloween costumes; it's not sexiness per se but rather homogeneity and lack of imagination in Halloween costumes that they lament. See the Take Back Halloween! About page for more details.)
My favorite costume on that site, so far, is actually one that had occurred to me before as someone it would be cool, and relatively easy, to dress up as: the famous female pharaoh Hatshepsut. Here's what Take Back Halloween! says about her:
Hatshepsut (ca. 1508-1458 BCE) was an extremely successful pharaoh whose reign was full of accomplishments --- important trade missions, gorgeous architecture, a booming economy. But the thing she's most famous for, at least nowadays, is that she had herself depicted as male on her monuments. There she is, King Hatshepsut, striding across the ancient bas reliefs with her broad shoulders and her beard ... it's a little weird until you understand what's going on. The role of pharaoh was gendered male in ancient Egypt, and Hatshepsut was just assuming the badges of office. She wasn't pretending to be personally male, and the texts unmistakably refer to her as female: "she" is the beloved "daughter" of Amun, destined to rule, and so forth. But Egyptian iconography and religion called for the pharaoh to have a male form, and so Hatshepsut had herself depicted with beard, kilt, the whole bit.
Take Back Halloween! suggests a standard dime-store Egyptian Queen costume, with the stripey headdress of a pharaoh substituted for whatever crown the costume comes with.
I would also wear a cardboard cartouche around my neck on a string, with (if I could find them) the hieroglyphs spelling Hatshepsut's name painted on it.
Another thing I thought would be fun to add to this costume, to throw a little gamer-geekery into the mix, would be to wear shoes evoking the "Freudian slippers" card from Munchkin, which allow your character in that game to function as whatever gender you say they are, even both at the same time. I thought that would be particularly a propos for Hatshepsut, who is female, but yet also male in her role as Pharaoh.
They also have lots of ideas for mythological-character costumes, which is another area of geekery that is dear to my heart. I was actually just pondering the best way to make a Gorgon costume that wasn't just a bunch of rubber snakes braided into one's hair --- the Gorgons, depending on what version of the myth you're reading, might have talons of bronze, wings of gold, and tusks like a wild boar or hippopotamus, or they might just be scaly and dragonlike; either way, "normal-looking woman with snakes on her head" falls short of the level of fearsomeness required.
Unfortunately, their Medusa costume is just a snake wig and a coat. Blah.