I just got back from seeing this band Bomba Estereo play in a free open air concert in the old city. They're from Baranquilla which is a town about an hour away from Cartagena, but this song, La Boquilla, is about a part of Cartagena which has the best beaches, and is populated by a surreal mix of the very, very rich and afro-colombians. During this song the singer (who dances more energetically than me, can you adam and eve it?) invited people to dance Champeta (african influenced music native to Cartagena) on stage with her. It was awesome, all this little kids and afro'ed dudes shaking their booties on stage, some of the girls move their hips so fast they seem to be vibrating. Also listen to Bomba Estereo - Fuego, the crowd went NUTS.
La Boquilla http://www.youtube.com/watch?v=u-vDLf7cmf0