"Joe's Garage" is the first real song on the 1979 album by the same title. It presents the main character's first musical experiences and his first brush with the law. Upon learning the guitar, Joe formed a typical suburban garage rock band. They got spotted by a record company executive in a go-go bar, signed a contract, failed to become stars, and broke up. This thread doesn't really fit with the rest of the song: as they play in Joe's garage, Mrs. Borg calls the police. A SWAT team surrounds the building and Joe is taken into custody. Since this is his first offense, he is well-treated and given the advice to "stick closer to church-oriented social activities" (which introduces the next song, "Catholic Girls").
"Joe's Garage" is a straightforward rock song, the typical kind of thing such a rock band would play (minus the vocal inserts and illustrative musical incidents). It is meant to be the group's hit song. Zappa actually released it as a single (b/w "Central Scrutinizer"), but it didn't chart. Live performances were often faster than the original tempo and provided a moment for inside jokes and on-the-road humor (such an example can be heard on You Can't Do That on Stage Anymore, Vol. 3). The song became a regular live feature in April 1980 and kept that status up to and including the 1988 tour. It was almost always performed along with "Why Does It Hurt When I Pee?"