Fairy Tail OVA

Separate stories from the main story-flow on the series, this pieces are meant to be a funny side of the guild or set in different "universes" at all. The first OVA has Lucy working on the girl's dorm as the Cat princess which give us a look at the daily life on a normal day on the dorm while Lucy has to find a precious item on it. The second one shows the guild as a normal academy and Erza's love story which ends up in a mess since she is strong as always and really bad when it comes to love. The third installment has Erza, Natsu, Grey and Lucy accidentally travelling to the past to when they where children.

Synopsis from Anime News Network