Oh dear lord!
This is, BY FAR, the most disturbing thing I've ever seen. Click on the link, it'll open in a new window. Once the clip is loaded, press the yellow button to view, and turn the sound up.
Some background here: Rainbow was a well-respected british children's show in the 70s. The cast made this for themselves, as a private joke. This was never meant to be distributed, except it made it onto a blooper reel and the rest is history :)
Watch all of it. It's sooo wrong, on sooo many levels.