Nozomu Itoshiki is still the bizarre teacher of the even stranger Class 2-F. He attempts to teach his students the negative aspects of the world and society, only to have each circumstance thrown at his face whenever he tries. With more students and friends than before, Zetsubo-sensei's life becomes harder and crazier than ever before. (Source: ANN)

A new Sayonara Zetsubou Sensei OVA.

More crazy antics abound as Nozomu Itoshiki (a.k.a Zetsubou-sensei), who is the worlds most negative person, tries to teach class 2-F about how life is filled with despair and darkness. A harder task than it first may seem, with his students being far from ordinary themselves, including the likes of the most positive girl he has ever met, his very own stalker, a foreign exchange student with split personalities and a perfectionist acting class president, due to the fact the real class president can't be seen by anyone, among others. (Source: ANN)

During a snowy day just before Christmas, Mizuki Tateno, a girl with a twisted personality, moves into the house next door to university student Fujioka Junsho. Mizuki says I hate Christmas. Why does she hate Christmas? Why does she have to live alone in a big house? An incident occurs right after Christmas and Mizuki's past is revealed. (Source: Wikipedia, translated and edited)