Ah yes, the "Happy, Happy, Joy, Joy" song. It's from the cartoon "Ren and Stimpy". It's a funny in a weird way cartoon. Here's one of the lines from the cartoon:
Ren: "You know how many other men tried to impregnate that barren wasteland [Stimpy]? There's de milkman ... de mailman ... de refrigerator repair man ... dat Jehovah's Witness bastard!"Stimpy: "Don't forget about that Boy-scout troupe!"
Ren: "Dat's right! Not even those strapping young lads could seed dat soil! It took a REAL MAN to put a brat in dere! Yep, my bullets were firing dat day!