Museum of the Confederacy, not too far from the D-Day museum - it's small, but interesting.
The zoo is pretty cool, at least see the swamp exhibit.
The aquarium.
Antoine's is an old style New Orleans restaurant and very good. Don't miss the oysters Rockefeller.
Mother's for the best po' boys in the world.
Frank's on Decatur St. for the best muffaletta.
Cajun Cabin on Bourbon for Zydeco music.
Original French Market restaurant on Decatur for oysters, crawfish, and Turbo-Dog!
The military museum at Fort Jackson, call first, it was flooded during Katrina and I don't know if it has been repaired.
Laizze la bon temps roule!
Damn, I wish I was there.
ETA: Lafitte's blacksmith shop on bourbon for a bourbon, what else.
And... Don't go outside the quarter at night. Be careful around the edges too.