From the Threadhead Cultural Foundation website (http://thrfoundation.com/events-2013/): 

No, it’s not a typo…. it’s the hottest ticket in town during Jazz Fest! Held each year on the Tuesday between Jazz Fest weekends, the enormously popular Patry features a huge line-up of New Orleans musicians as well as cameos by various surprise guests. The venue for the 2015 Patry is again at the Old Ironworks. Generous sponsorship from businesses and individuals, together with much sought after raffle items, allows the Foundation to raise substantial sums for our programs.  See the tab at Patry 2015 for more information and to purchase tickets.