At Gumbo Ya Ya, the food might be hot, but the music is always hotter. (Quite a feat for an event serving Cajun sausage and spicy boiled shrimp.) That truism will certainly apply to this weekend's annual Mardi Gras in the District festival, at which nine bands will deliver crowd-pleasing performances of Cajun, zydeco, blues, funk, rock, soul, hip-hop, R&B, and reggae music.