"They just played a sold out show at Madison Square Garden - what a dump".
- David Letterman.

Dave Grohl is not only the most fan friendly performer in all of rock but he is also the most performance and business savvy.

He knows what will work and he knows who it can work with.

Last night, he and his band Foo Fighters (there's no "The" as I was pleased to see the shows host noted) appeared on "The Late Show with David Letterman" on CBS where they performed with a very, very special guest.

Rock and Roll Hall of Fame ballot- er Joan Jett.

One of my very longtime favs'.

Foo's are currently on the road promoting their recent effort 'Wasting Light' and the tour stopped at Madison Square Garden on Saturday night where the divine Ms. Jett also joined them.

"Do you guys wanna learn how to f%#&*@ rock and roll!?", Grohl asked the crowd.

"You got the best f%#&*@ teacher in the world RIGHT NOW!!" he screamed gesturing towards the tiny, dark haired, leather clad goddess standing behind him putting on her axe.

Check out last night's Letterman jam!