Here’s a note about karaoke in NOLA from last summer.
Depending on where you are staying – the Charles St. Line streetcar as mentioned takes you through a very good informal tour of town, through the Garden District and to the Audubon Park/Zoo and Loyola campus. Then there’s the Canal St. Line which has two different ends: the historic cemeteries, which are an interesting exploration, and the Art Museum/City Park (it does pass you through ordinary bleh urbanscape before you get there, though). One can take a steamboat ride or, for the truly cheapo version of sailing the Mississippi, ride the Algiers Point ferry there and back - free for pedestrians, at the end of Canal near the Aquarium, 2 blocks from Harrah’s Casino.
As mentioned before a walking tour of the architecture is something to check out, but there’s also the WW2 Museum downtown, quite the place for history buffs. Royal St. in the daytime is a place for street performers and antiques. One important thing if doing any walking, though: check the weather report. A hot summer day in NOLA will make you feel the pain of a boiled crawfish, it’s a steambath.
As TriPolar mentioned, good luck with the food… Jeebus, that’s one heavy-eatin’ town!