How many violinists does it take to change a lightbulb?

- As many as you like, there'll still be more than enough left in the orchestra.

How many viola players does it take to change a lightbulb?

- As many as you like, no one will notice they've gone.

How many timpani players does it take to change a lightbulb?

- Just one is fine ... as long as she's back in time for bar 786.