gaku buru

Light novel series written by Honda Tooru and illustrated by Komone Ushio.
Title: がく×ぶる
Official website: http://dash.shueisha.co.jp/-gakuburu/index.html
Japanese Wikipedia: http://ja.wikipedia.org/wiki/%E3%81%8C%E3%81%8F%C3%97%E3%81%B6%E3%82%8B