Redditor TheOnlyJuanEver attends an elite public high school in Mexico City. For years they’ve set aside a day for gender-bending dress called Skirt Day. The boys dress in skirts (or in rare cases, a dress), and the girls all wear ties. He says,
It's a movement to support gender equality and to fight gender roles in society. I don't know exactly how it started, it was celebrated long before I got into the school.
Sadly, my highschool is the only one I know of that does this.
Almost everyone participates, and they all have a great time with it. You can see that they don’t have to worry about the school administration measuring how short the skirts are. See 22 pictures in this imgur gallery.
Of course, if they really wanted to experience what it’s like to dress as the opposite sex, they’d have High Heels and Pantyhose Day, but none of the guys would want to participate. The same school went all out for Costume Day a few weeks ago.