On a late-November Tuesday night in New Orleans, bodies rubbed up against one another at Bullet's Sports Bar as Kermit Ruffins coaxed high notes from his trumpet. The music was infectious, the regulars who packed the neighborhood joint for this weekly gig deeply committed to it. The next night, Mr. Ruffins was back. This time, more than a dozen thick cables snaked their way out onto A.P. Tureaud Avenue and into a sound-company trailer. It was no regular gig: "Treme," producer David Simon's latest series for HBO, was taping inside.

After an enthusiastic response to a pilot episode from HBO executives and the end of the hurricane season, Mr. Simon is back in New Orleans to complete the 10-episode premiere season, scheduled to begin its run in April.