1School Days (ONA)
The story is about a love triangle between the male protagonist Makoto, and the two heroines Kotonoha and Sekai. Makoto develops a love interest in Kotonoha, a girl in the same year but different class. Although they both take the same train to school, she is unaware of his existence. His classmate, Sekai, manages to put the two together despite holding strong feelings towards Makoto.
2Valentine Days
OVA coming with the PlayStation 2 game "School Days L×H" It's a very funny comic spin on Valentine's Day, and much more lighthearted than the original series.
3Magical Heart Kokoro-chan
Originally an April's Fool in 2007, this one episode OVA is a spin-off of the School Days game by 0verflow, and shows Kokoro Katsura, the little sister of one of the main characters, from her other side. A mahou shoujo out to save the world, or something like that.