The Hollywood School of Rock

By Dana Flax

Like many disgruntled 9 to 5'ers, some Hollywood stars think of acting as just a "day job." Adrian Grenier, for example, hangs his "Entourage" hat at night, trading in the fast cars and hot chicks of the television show in favor of touring around with his band The Honey Brothers — and still getting a satisfactory share of hot chicks while doing so.

So, put up those fists, grab your middle fingers with your thumb and click through to rock out with Hollywood's gnarliest headbangers.

Scarlett Johansson, seen here performing with The Jesus and Mary Chain in 2007, released an album of Tom Waits covers last year to, um, mediocre reviews. But who cares? ScarJo can do whatever she wants.

Newly married to newly ripped Van Wilder (aka Ryan Reynolds), and most likely permanently glued to the casting finger of Woody Allen, Scarlett Johansson should just take the flailing state of her music career in stride. Or just keep using it as an excuse to collaborate with more dreamy musicians like Pete Yorn.

Just because Dennis Quaid has been relegated to the "dad" role in the last couple of years (see: "In Good Company," "The Rookie," etc.) doesn't mean he can't shred his axe with the best of them. When not filming, Dennis plays pure, unadulterated rock 'n' roll with his band, The Sharks. Doesn't hurt his rock star cred that he's still putting out that sexy vibe — sexy dad vibe — that is.

Jada Pinkett-Smith: Hardcore metalhead. Nope, we're not kidding. On breaks from being Will Smith's doting wife and baby mama, Jada sings songs like the subtly macabre "Bleed All Over Me." As one of only a few chicks in an otherwise dude-centered metal music scene, I'll give her props for trying (if not for her music). In the immortal words of Pitbull, "Go, girl!"

Madoff be damned! Kevin Bacon's gonna rock you, and he's gonna rock you hard. Well, he'll at least entertain you with some soft, tambourine-laden tunes he's cooked up with his brother, who tours with him as the Bacon Brothers Band. And here we thought rock stars were supposed to be darkly mysterious!

Nope, Jared Leto's not training to be in the Gestapo — he's performing onstage with his band 30 Seconds to Mars. Wonder why he hasn't had many leading roles since that creepy turn in "Requiem For a Dream" (and even creepier turn as John Lennon's killer in "Chapter 27")? Well, he's just too busy being super down-low indie, which really only appeals to a select group of loyal "My So-Called Life" fans.

Performing with both her former band Juliette and the Licks and current band The New Romantiques, Juliette Lewis takes the tight pants tradition of rock stars to the Nth degree, painting the stage red with her zippered crotch. Who needs a boyfriend like Brad Pitt when you probably score a ton of dude groupies? (Then again, maybe not.)

During the peak of his fame in the '90s, Keanu Reeves took time off from filming questionable sci-fi flicks like "Johnny Mnemonic" and "Chain Reaction" to create edgy grunge music. His band almost named themselves Small Fecal Matter, and later BFS (Big F—— S—), before settling on the name Dogstar.

Unfortunately the more optimistic name didn't make much difference. They peaked early, opening for Bon Jovi back in 1995 and releasing two lukewarm albums before breaking up in 2002.

Perhaps the most successful rocker on this list is Jack Black, whose comedy acoustic band Tenacious D has had successful albums, tv shows and movies alike. I mean, who could resist a track where Jack Black humorously pranks a Burger King drive-thru operator? It's like the Jerky Boys set to truly awesome music!

This one may not have been a surprise to you, considering he made it on our list for the 25 Most Ridiculous Celebrity Album Covers — and the video for his cover of "Respect Yourself" is vintage VH1 gold — but Bruce Willis fancies himself a blues singer in his spare time. Let's just say that his music is about as digestible as a greasy, soggy, yet delicious, Planet Hollywood burger. (Willis co-owned that successful biz, too, as your stomach may or may not want to recall.)

Who's that squinting and all smirky over there on the mic? Why, it's none other than "Bad Santa" Billy Bob Thornton himself. Although his country rock band, created in 2007, is called the Boxmasters, we would've preferred if it was called rock-a-Billy Bob Thornton. 'Cause, after all, he's pretty much the one reason I'm listening to that 'tucky twang.

Faux Mormon and weather-fanatic Bill Paxton used to make really awesome music with his band, Martini Ranch. That kind of sounds like a Jimmy Buffett song, only slightly classier, right? Anyway, their album, Holy Cow, didn't do terribly well on the charts, but it's okay — Bill's probably got enough on his plate with those three nutty HBO wives and their mail-order catalog-caused credit card debt.

Another successful musician is actor Jason Schwartzman, whose former band Phantom Planet has been immortalized as "that 'O.C.' song band." Not to mention the fact that their surfer rock actually makes a pretty good soundtrack to a long drive up the California coast. Schwartzman's new project, Coconut Records, has also enjoyed a few hits in the last couple of years. Keep on doing what you're doing, son — I'm counting on you to hold up that illusive credibility of actor-slash-musicians.

Next on the list of twerpy-named celebrity bands is Thunderbox, otherwise known as the Steven Seagal blues vehicle. I've never seen one of their shows, but I'm hoping that there's some radical martial arts, or at least grizzly furrowed brows, incorporated into his performances.

Jeff Goldblum moonlights as a jazz musician, performing with a band called the Mildred Snitzer Orchestra. I'm not sure what the name has to do with Jeff Goldblum, or jazz, but then again, a lot of stuff he does is just way over my head. Like, oh, "Jurassic Park." Also, I'm just really glad he isn't dead.