Prison Rabbit… is an animated series produced by Kanaban Graphics for MTV Japan. Each episode is about 90 seconds long and has no speech.
The series, whose correct title is ‘Usavich’, depicts a pair of rabbits incarcerated in a Russian gaol and their escapades. I find it immensely funny, but some of my friends don’t see why! I think it may be similar to Marmite in that respect.
You can see more at the official site and a variety of fan sites if you search a little.