2) You find a song that is really really cool. Like, oh, off the top of my head, "Baby Got Back" as covered by Jonathan Coulton.
3) Copy the song and arrangement note for note, but with your cast singing it. You know how Vanilla Ice changed one note in the bass line for "Under Pressure" and claimed it was completely original for "Ice Ice Baby"? Well, that shit's for pussies. Exact copy.
4) Put the song that sounds like your cast doing karaoke up for sale on iTunes, crediting Sir Mix-A-Lot who did the original but ignoring Coulton.
5) When Coulton bitches about this, tell him that he should be thankful that his song is getting exposure. Pray that he doesn't notice he's not credited at all, so no one watching the show knows of this exposure.
6) Be sure to thank the DevianTARTs for showing you the way.
Class dismissed. I'm busy writing a Sound Waves musical, and it will open with Rhapsody and Melody singing Jagger and Bowie's "Dancing In The Streets."