I think Zap Mama is one of the best musical groups to ever have existed, and I've seen them on every US tour they've done so far, but I'm going to miss this one. So I'll rave about them some other time. A brief description: Women of mixed Swiss/Congo origin, vocal based music, a combination of English, French, Swahili, and nonsense syllables, percussion, dance, and color, powerful stage presence, and interesting sound tricks. They started out almost entirely a cappella and over the years have included more and more instrumentation, but their music is still focused on vocal sounds. They've added, in particular, percussion, rhythm instruments, and hip-hop influence. (the fact that Marie Dualne, Zap Mama's founder and leader, is or at least was dating Michael Franti (aka Spearhead) may have had something to do with it... :)
BTW, Education First is on right now! I'm heading over there to catch the Dresden Dolls.