Rock machine Dave Grohl broke his fibula on stage at a Foo Fighters show a few days ago and — in true rock machine fashion — continued the show from a chair after medics set his leg. Today, EVB released a fun online gadget to let you virtually sign his cast. Submit your message to Dave on Twitter by posting with #SignDavesCast. All posts will appear on Dave’s Virtual Cast. And as many as possible will be printed on an actual cast sleeve that will be sent to Dave.