Kellie Davis lives in Normal Heights in a studio apartment with her boyfriend Tom and their dog Phoenix. Kellie is a recent UCSD graduate with a film degree and works as a production assistant for Liberty Studios in Mira Mesa. "Preproduction," Kellie says. "I'm mostly responsible for casting all the extras -- taking care of a lot of the random things like renting equipment that we're gonna need on location, reading the script. On location I check in the extras every morning, get them in and out of wardrobe, makeup, get all the paperwork filled out for the day, and do whatever the AD [assistant director] wants me to do." Kellie is 25. She owns an off-brand MP3 player. "It's a cheap little one I got at Wal-Mart. Muvo, or something like that."

Since June, Kellie has also been a member of the San Diego Derby Dolls. "I saw an ad on craigslist [craigslist.org]. It said, 'Any girls in San Diego wanna do roller derby?' And I thought, 'I like to skate. Sure.' I knew it was a rough sport, but...I used to play in-line hockey when I was [a senior] in high school."

She explains that a roller derby team is made up of jammers and blockers. "The jammer scores a point for every blocker on the opposing team that they pass." The sport, she says, comes from the blockers trying to prevent the jammer from getting through.

"In the past few years roller derby has kind of just popped up [again] in all the major cities across the U.S. There's no national league or set of rules that they all adhere to. So, like, there are a lot of them that are really theatrical, WWF-like. They do all the fake hits and overexaggerate everything, whereas in L.A., they make it a proper sport. You can't just punch somebody. There's limits to what you can do. You can block them, you can knock them out with your body, but no deliberate hands-on kind of thing. I think it makes it more of a skilled sport that way.

"There's no, you know, big old muscular chicks, weightlifters out there. One of our best skaters is tiny. She's maybe five feet [tall] and maybe a hundred pounds. She's really fast and she's kind of bony. She hurts when she hits." I ask her why roller derby seems to be, for the most part, a woman's sport. "There's an appeal to the broader public when girls do it," she says. "There's sex appeal." While wearing helmets and pads? "There's that too," she says, "but we're skating around in our skirts...fishnet stockings. In the costuming, there's a bit of camping it up.

"I've thought about using my MP3 player when I've been at practice. Sometimes you have to just skate around a hundred laps, and it gets a little boring. Music helps you concentrate less on [the fact that you are] getting extremely cramped up or whatever and just skating in circles. I've got various things downloaded. Rock. Oldies. Anything with a beat, really.

"I have...I don't know, hundreds of songs. I usually download." Kellie favors LimeWire. "Some of them are [ripped from] CDs. Musically, I like anything that's danceable, upbeat, fast." The Muvo goes everywhere Kellie goes. "I used my MP3 player while I was on set last week. I had my walkie-talkie in one ear," she says, "and my headphone in the other."

Kellie's Top Ten:

1. "Black Betty,"

Spiderbait

2. "Switch," Will Smith

3. "Video Killed the

Radio Star," the

Presidents of the United States of America

(cover version)

4. "Jump Around," House of Pain

5. "Let's Get It Started," Black Eyed Peas

6. "Hey Mama," Black Eyed Peas

7. "Pump It Up," Elvis Costello

8. "You Shook Me All Night Long ," AC/DC

9. "Vindaloo," Fat Les

10. "Speedracer," Everclear