Here are some I found on the web.
What’s the definition of an optimist?
A harpist with a tuner.
If you were lost in the woods, who would you trust for directions, an in tune harpist, an out of tune harpist, or Santa Claus?
The out of tune harpist. The other two indicate you are hallucinating.
Why are a harpist’s fingers like lightning?
They rarely strike the same chord progression twice.
What’s the difference between a Celtic Harp and a Concert Grand Pedal Harp?
A Pedal Harp burns longer.
A harp is a nude piano.
But a piano is a harp in a coffin.