Two words: Music, Food (not necessarily in that order)Ship'scat's URLS are a good place to start, but beware! The quantity, quality, and variety of live music available in NOLA is bewildering.
At least once, grab a go cup and take an evening stroll down Bourbon street. It is old, lewd, dirty, tacky as hell, touristy, and wonderful. The doors will be open and the music will be loud so you can spend an entire evening just sampling the musical smorgasbord. If you hear something you like, go on in, buy an overpriced Bud and enjoy for a while, then move on.
Eat early, eat often, and eat to excess regularly. Forget about eating healthy for a day or two. The big name restaurants are truly world class, but you can pick a neighborhood restaurant you've never heard of at random and there is a good chance you will have one of the best meals of your life.