Dave Grohl, dude.  Dave.  GROHL.  Dave Grohl has been in the White House several times. He is friends with Paul McCartney. His band the Foo Fighters is very, very, very popular. You almost forget--almost--that he was a drummer for Nirvana, with someone named Kurt Cobain. How did Dave Grohl ever escape the shadow of that band?  How did Dave Grohl become America's favorite rock star musician? How did Dave Grohl write a book that is now on sale in Costco? Apparently by being just the nicest guy. Martha and Christian kick off season four by sitting at the feet of America's favorite dude named Dave and listen to this "Storyteller" spin the yarns of his greatest do-or-die moments; and for Dave, they're ALL do-or-die.