A Scarleteen user's final project for her Feminist Theory class, these two student-made sex ed videos linked through the accompanying blog are informative and a lot of fun.
The Equipment, part one
This section of the video covers topics such as physical anatomy (and what the parts do), arousal, vaginal fluid, semen, and intersexuality.
The Equipment, part two
This section of the video covers topics such as gender identity, sexual orientation, the characteristics of semen & vaginal fluid, and size.