Everyone knows Jason Schwartzman was the drummer for Phantom Planet, and Jared Leto’s group 30 Seconds to Mars has been winning awards for years, but some of your favorite Hollywood personalities have, not so quietly, been maintaining musical passion projects on the side.

South Park creators Trey Parker and Matt Stone formed the satirical comedy band DVDA with fellow South Park crew members Bruce Howell and D.A. Young over ten years ago. The band’s music has appeared in several productions by Parker and Stone including on South Park, and the films, South Park: Bigger, Longer, and Uncut, Team America: World Police, and Orgazmo. The band has several unreleased singles, and opened concerts for Ween and Primus. In case you’re wondering; the bands name is an acronym for a sexual position.

Val Kilmer played Jim Morrison in The Doors, and took to the theatre to play the role of Moses in The Ten Commandments: The Musical, but that’s not enough for “Iceman” as he’s now released an album with frequent co-star Mick Rossi. Sessions with Mick includes covers as well as original work, and all proceeds from the album are donated to Kilmer’s favorite charities. Sales were strong, but critics were divided, with some trashing the album out right. New York radio comedians Opie and Anthony dedicated a major chunk of a morning with Jim Norton, Louis CK, and Bob Kelly in the studio all ripping it apart track by track.

Robert Rodriguez, the groundbreaking director of films such as Sin City, Grindhouse, the Mexico Trilogy, Machete, and the Spy Kids franchise, has been known to play alongside Spanish language band Del Castillo as a sit-in guitarist and vocalist. Together they formed the band Chingon, and recorded an electric rendition of the Mexican classic song, “Malaguena Salerosa.” Frequent Robert Rodriguez collaborator Quentin Tarantino was so impressed with the song that that he re-did the ending sequence of Kill Bill Vol. II to fit the song in. Chingon performs frequently at Robert Rodriguez-hosted premieres for his own films.

Bruce Willis is more than just one of the biggest action stars in Hollywood. He’s a blues man. Together with his band, The Bruce Willis Blues Band, he’s toured the country, and along with Bruce Willis and The Accelerators he has even gone overseas to Iraq in 2003 to entertain troops as part of a USO show. Bruce Willis and The Accelerators have been widely praised for their live performances, and have been around for over 15 years now, showing no signs of stopping any time soon.

Steven Seagal is mostly known as that guy who stars in those ridiculously awesome ‘80s action movies that you find yourself watching at two in the morning. But when he’s not karate chopping double agents on oil rigs, he’s playing old fashioned blues and rock and roll as the frontman for Steven Seagal & Thunderbox.

Adam Brody is probably best known as The OC’s Seth Cohen, an indie music obsessed nerd that made teenage girls swoon. So it seems only natural for the real life Seth Cohen to be a bit of a nerdy drummer for an indie band that probably makes teenage girls swoon.

Adam Goldberg is absolutely phenomenal as the hyper-anxious and sarcastic neurotic Jewish characters he’s been playing since he was a practically a kid in Dazed and Confused all the way through to The Hebrew Hammer. His quick, stammering persona is like a modern day version of Woody Allen, but with an air of cool. As Woody Allen has been playing jazz clarinet for nearly his entire career, Goldberg recorded songs for his group LANDy’s debut album over six years. The album, Eros and Omissions, was released in mid 2009 to critical acclaim and featured collaborations with The Flaming Lips’ Steven Drozd, and Earlimart’s Aaron Espinoza.