Aside from its funky street murals and psychedelic art shops, the main reason to come to Havana's high temple of Afro-Cuban culture is for the frenetic rumba music that kicks off every Sunday at around noon. For aficionados, this is about as raw and hypnotic as it gets, with interlocking drum patterns and lengthy rhythmic chants powerful enough to summon up the spirit of the orishas (Santería deities). Due to a liberal sprinkling of tourists these days, some argue that the Callejón has lost much of its basic charm. Don't believe them. This place can still deliver.