Woman goes into a trailer to use toilet and in the toilet in a member of the band moon

In Venice Beach, naive Midwesterner JB bonds with local slacker KG and they form the rock band Tenacious D. Setting out to become the world's greatest band is no easy feat, so they set out to steal what could be the answer to their prayers... a magical guitar pick housed in a rock-and-roll museum some 300 miles away.