Dr. Tatiana's Sex Advice to All Creation (2005)

It is perhaps the most original science documentary ever made. Dr. Tatiana's Sex Advice to All Creation is an all-singing, all-dancing musical. No joke: there are 14 original songs, including the hermaphrodite song and the female promiscuity song (which features the refrain, "I want to do it again, I want to do it again, my mother always said you can't have too many men"). And that's not all. Dr. Tatiana interviews scientists, chases wild banana slugs and elephant seals, dispenses sex advice in her clinic, and conducts a Jerry-Springer-style TV show within the TV show. But where Springer's guests are troubled humans, Dr. Tatiana's are penis-fencing flatworms, sexless rotifers, and fruit flies that use drugs to keep their mates faithful.