All jazz groups ultimately descend from the brass band. The legendary Buddy Bolden, often credited with being the first true jazz musician to improvise freely, led the most popular brass band in New Orleans at the turn of the 19th century. A few years later, Louis Armstrong learned trumpet in a reformatory brass band. Since then, countless musicians have learned the basics of their art in high school, union or military brass bands. Today in New Orleans, at nearly all social occasions, from birthday parties to funerals, brass bands perform live.

But more important than all that, they're a lot of fun. The marching second-line rhythms, interweaving horn lines, husky call-and-response vocals and huge, deep farting noises all sweep together into good-time music. The Dirty Dozen was one of the first revivalist brass bands, and it's still one of the best. They have been pumping out party music for more than 25 years and know how to serve it up right.

Now's a good time to catch them live. The Dirty Dozen's most recent CD, "Medicated Magic," is one of their best. The addition of keyboards, expanded drums and rhythm guitar take their sound beyond the traditional arrangements of their past work, making it both funkier and jazzier. Still, the songs never stray far from New Orleans, with selections from The Meters, Dr. John, Allen Toussaint and Professor Longhair. Key guests also help make the album special. John Bell from Widespread Panic, Olu Dara and new chanteuse Norah Jones all deliver vocals. And with DJ Logic on turntables, Robert Randolph on pedal steel guitar, and Dr. John on piano and vocals, it's like one big party.