The Zelda rap is in the very first Legend of Zelda commercial from the 80's. It features two stupid kids who can't act. One of them pulls out his Nintendo Newsletter and shows the other some screenshots of the 'new' Zelda game. All of a sudden one of them pull out what might be a bootleg copy of the game, and puts it into his NES. For some unknown reason, the two start an inpromptu rap song, which goes as follows:
"It's The Legend of Zelda and it's really rad!
Those creatures from Ganon are pretty bad!
Octoroks, tektites and leevers too,
But with your help, our hero pulls through!
Yeah, Go Link, Yeah, Get Zelda!
Wikki Wikki Wick!"
The commercial then cuts to the announcer, who says that your parents need to help you hook up the NES.
When I saw this commercial and heard the Zelda rap, I was both horrified and amused at the same time.