Jess: What... What did you... Of course! Of course you were scheming with Schmidt.
Nick: Jess, I didn't do anything.
Jess: You think that Schmidt and Winston would be smart enough to duct-tape the sound board? That's brilliant! Plus, we both know that this is your CD.
[flashback to Nick rocking out in his car with Jess in the passenger seat:]
CD Player: Where did you come from, where did you go? Where did you come from, Cotton-Eyed Joe?
Jess: Why did you need me for this?