Answer to this week's riddle

Travis Hale

Again, the riddle:  

"Arbitrage" is a recent, if controversial, explanation of what ephemeral fast food product?

Answer:    According to Willy Staley, McDonalds's McRib.  Read more at http://www.theawl.com/2011/11/a-conspiracy-of-hogs-the-mcrib-as-arbitrage.