The 38-year-old has written and produced original music for dozens of hit movies, including "Transformers," "Night at the Museum" and "Alvin and the Chipmunks" (whose soundtrack went platinum and won Ali a 2008 American Music Award).

Then I get a call on my cellphone from the 310, an LA number. It's the guy who licensed my song in "American Pie 2." He's making a movie called "Big Fat Liar," and tells me, "My back's against the wall. I need four songs by tomorrow, and I only have $7,500 apiece." I set the phone down and look up at the sky and whisper, "Thank you."

Right now we're working on "Alvin 2." I've got six production rooms, and 10 people coming in full time. It's like a manufacturing plant. We might hum a groove, and someone will go off and lay down a bass line. Then he'll hand it off and someone will add keyboards, and we'll start on another. We'll probably record 200 songs for that movie, and 18 will make it in. Ninety percent will be Chipmunks singing. That's us, by the way, not the stars. We'll sing everything at half-speed and then speed it up for the chipmunk effect. It's kind of funny. I'll take a call from high-level executives at Fox, and they'll ask, "So, what do the Chipettes sound like?" This is my job.