Anne Happy♪

The story centers around class 1-7 of Tennogofune Academy, where all the students with "bad karma" or misfortune seem to have been gathered. Hibari, a student in this class, meets the unlucky Hanako and the perennially unhealthy Botan on her first day of school, and together they try to find a way to turn their school life into a happy one.

Link:
AnimeNewsNetwork (anime).