Shin Sei Yariman Gakuen Enkou Nikki

Based on an indie game by Orcsoft, this captivating anime tells the story of Saiki Yasuo - a 45-year-old office worker who's been living alone since his wife left him after 20 years of marriage. He spends most nights drowning his sorrows in booze until one fateful night when he meets this fine piece from St. Marian Academy, looking for some fun.

(Source: RealFansUnite)