The official daytime shows at the fairgrounds are half of what the festival is about. Each night, hearty breeds of music lovers stay out until sunrise soaking in the voodoo-induced vibrations at haunts all over the country’s funkiest city. Odd couplings, featured guests, and surprise sit-ins are Jazz Fest hallmarks. Of course, New Orleans A.K.—“After Katrina”—is a different place, and the festival has become a barometer. Jazz Fest 2006 ushered in the rebirth of a region ravaged by the worst natural disaster in U.S. history. This year’s event reflected a palpable sense of homecoming and rebuilding.