OCEANSIDE -- Local bands will take to the seaside Oceanside Amphitheatre stage Sunday afternoon, rocking out at an anti-drug event designed as an alternative to a counterculture holiday that celebrates marijuana use.

The concert -- called "420 Remix: A Celebration of Sober and Drug Free Life Choices" -- is being put on by the North Coastal Prevention Coalition, the Vista Community Clinic and the Tri-City Prevention Collaborative. The goal is to give teenagers and their families something to do together on a day that some associate with smoking marijuana.

"Marijuana has become so normalized in our culture, but it's not that safe, benign drug like it used to be," said Victoria Carlborg, media and prevention specialist with the North Coastal Prevention Coalition. "We're remixing what 420 means. We're hoping to educate, but at the same time we don't want to preach."

The number 420 (or 4/20, for the April date) has long been used as a reference for smoking marijuana. Urban legends claim it's the penal code section relating to marijuana use, the police radio code used for marijuana arrests, or the number of chemical compounds present in cannabis. None of those myths are correct.

Officials say the origin of the phrase more likely stems from a group of 12 students who attended San Rafael High School in 1971 and would meet at 4:20 in the afternoon to smoke. They used the number to remind each other of their appointment and the phrase apparently spread and grew in popularity, according to debunking Web sites such as Snopes.com.

Though local nonprofit groups began hosting an alternative "420" event in 2004, this is the first year it has featured a battle of the bands.

At Sunday's concert, each of the competing bands will get 20 minutes on stage to strut their stuff and impress the crowd. The band that rocks the most, as determined by three judges, wins an interview and guest appearance on Radio Sophie 103.7's "Unsigned Sundays," and the chance to play another 20-minute set.

"Besides being a lot of fun, there's also the (drug awareness) policy aspect to it," Carlborg said.

April 20 has been designated as "Sober and Drug Free Life Choices Day" by the San Diego County board of supervisors, and by the councils of several cities, including Oceanside, through the efforts of the North Coastal Prevention Cooperative.

"We're taking the day back from the stoners," Carlborg said.

In addition to the band competition, this year's event features a rock climbing wall and educational booths.

The event takes place from 2 to 6 p.m. Sunday at the Oceanside Amphitheater. More information about the event and the organizations behind it can be found at www.northcoastalpreventioncoalition.org.