What you need: a white tank top, a pair of scissors 

Regina George, from the seminal feminist project Mean Girls, is a fashion icon even on Halloween. Get inspired by her confidence and start a trend just like she did by intentionally cutting out two small holes in a white tank top to reveal your colored bra underneath. Finish with heels and a short miniskirt. If you can, quote Regina George at least one that night. This is a great last-minute costume for both boys and girls.