A week after Hurricane Isaac squatted over Southeastern Louisiana, bowel movement jokes fill a room on Tulane Avenue. A deejay drops intros for comedians who lament, decry and ridicule recent events. Power outages and long drives are laughing matters when the levees work. Tonight the audience lounges on white chairs and sips cold drinks in crisp air-conditioning. At the center, generating the most laughs and controlling the pace, is our host,