Hah, I just got back from NOLA for the same reason. I've been a few times before though...depending on the type of people in the group, walk to Jackson Square, see the cathedral, walk the market (immediately past Cafe du Monde). If they're more open to sight-seeing, hop on the trolley and just take it up for a while. Get off on Magazine St, eat/shop...some beautiful neighborhoods out there.
If you're all into live music, I also highly suggest getting over to Frenchmen St. It's about 2-3 blocks East of the edge of the French Quarter and that's where you'll find a bunch of open clubs/bars like D.B.A., Snug Harbor, Spotted Cat, etc. It's also open container like the FQ so if you don't like a band, just take your drink and leave.