Every year The Allman Brothers Band hold court at New York's Beacon Theatre for an extended run and 2009 was a very special year for them as it was the 20th anniversary of the event.
And being a jam band, they celebrated with a wide array of guests each night. Perhaps most notable were two nights with Eric Clapton -- notable because given the ties between the Allmans and Clapton and both their propensities for collaboration, they'd never appeared together on stage before.
Check out here for tons of Youtube coverage and directly for the songs with Clapton: Little Wing, Dreams, Why Does Love Got to Be so Bad, Layla, In Memory of Elizabeth Reed and Stormy Monday. Each song has multiple version on Youtube, some truncated, some continued over multiple videos, so you might have to hunt around a bit for the best version.
For me, one of the coolest things about these performances is that we get to see three generations of great players together on the same stage: Clapton, Warren Haynes and Derek Trucks, all three amongst Rolling Stone's 100 greatest guitarists. Clapton is #4, Haynes is #23 and Trucks is #81. Also related to the ABB, Dicky Betts is #58 and the late Duane Allman is #2.