Trans-Siberian Orchestra

When the Trans-Siberian Orchestra debuted their symphonic take on Christmas music in the late-’90s, it sounded an awful lot like a novelty. In the years since, however, their progged-out, light-show-assisted tours have become an enduring traditionnot to mention a lucrative one. The group's recent tours have been raking in about $40 million a year, and the band has proved so popular that it split into two entities to better capitalize on the seasonal demand. The group doesn’t want to be entirely pigeonholed as a Christmas act, though. In 2009 they released their second non-holiday album, Night Castle.