I found out after-the-fact that they just opened up a shutter on Bourbon St. and there was Foo Fighters playing a secret show featuring Trombone Shorty for their New Orleans song on the album.
For those that don't know, the idea for both the album and the show was that there are several "music cities" with their own unique flavors, and the idea was to write a song in each of the cities with influences from that city, and then perform it there.
Will be pretty sweet. FWIW, I'll be seeing Foo at Voodoo Fest in a week.