Foo Fighters pranked the Rockville crowd, when Dave Grohl pretended to play Van Halen, only to reveal Wolfgang Van Halen backstage.
During the Saturday night headline set, Dave Grohl complained that,
“I never get to fucking solo.”
So Dave began to rip into the finger tapping part of Van Halen's "Eruption," only to later reveal Wolfgang Van Halen back stage playing the actual solo. Now that the crowd was in on the joke Wolgang would break into "Hot For Teacher" and wow the crowd once more, then give it back to the Foo's who went into "My Hero".
The joke mimics the Conan O'Brien guitar battle with Jack Black, when Slash was behind the curtain playing Conan's parts. A little bit of concert fun for all who came to see the biggest rock show of the year "Welcome To Rockville"!