"Break a Leg!"

David Grohl of the Foo Fighters falls off stage and breaks a leg in Sweden, and does one more song finishes set before going to the hospital:

After having his leg bandaged, Dave returned to the stage and finished the concert sitting in a chair. He told the audience: 'I may not be able to walk or run but I can still play guitar and scream.'

He completed the set alternately performing with crutches or sitting on a chair, according to footage shared by fans, immediately propelling him into music folklore.

You can see the actual fall at the link.