Somewhere behind all those people sits a jazz combo: The Society Jazzmen. They play every Sunday at De Fontein, a wonderful venue on the Strand in Mission Bay. What the Jazzmen lack in raw talent they also lack in craftsmanship and unity of intention. But somehow they make it all up with bonhomie and the warmth of familiarity. The most exotic song they played was Sunny Side of the Street, and everybody sang along and the place was packed. People from the audience came up for a song or two, and it was fun.