TakeLessons.com, an online service that connects music students with its instructors in more than 400 U.S. cities, is having a very good year. The company enjoyed increased same-city sales ranging from 12 percent to 28 percent each quarter of 2008 versus 2007, and 2009 looks even stronger, says CEO and founder Steven Cox. Thanks to American Idol, voice lessons are most in demand, followed by piano, guitar, violin, and drums.

TakeLessons's good fortune is part of an unexpected recession sweet spot for music. In 2008, a year in which auto sales plummeted and many retail stores struggled, musical-instrument sales tended to hold up, according to Music Trades. And some categories grew. In the first three quarters of '08, fretted instruments like guitars were up an average 4.3 percent.

It's not just kids signing up for lessons. Recent enrollees at TakeLessons were split evenly between under-18-year-olds and adults. Students include a Goldman Sachs investment banker and the CEO of a biotech start-up. "When push comes to shove and people decide whether to cut out the steak dinner or give up music lessons," says Cox, "they cut the steak dinner."