Apparently, as part of learning about gender awareness, a Yamanashi High School allowed students to voluntarily change uniforms with each other. I'm not sure how much you will learn by cross dressing, apart from broadening your horizons perhaps, but it gave the media an opportunity to take photographic evidence and prevent careers in politics for all the students.
「男らしさ」「女らしさ」を離れて自分や社会を見つめ直してみようと、山梨県富士吉田市の県立富士北稜高校で11日、有志生徒が男女で制服を交換して過ごす催しがあった。「セクスチェンジ・デー」と呼ぶ試みで、「sex(性)」と「exchange(交換)」の造語だ。全校の約4割に当たる299人(男子117人、女子182人)が参加した。
I'm not entirely sure you can swap uniforms if there are not an even number of boys and girls involved, but anyway, I hope everyone had fun.
Go on, have a screencap courtesy of Mulboyne's twitter feed.