Oh yes, The Murder of Roger Aykroyd — one of my favorites, and an excellent example of an "unreliable narrator."
I was thinking about a play I saw once. I feel like it was a Sam Shepherd play. The man on stage is (as I recall) guided and spoken to by some Presence, represented by a large hand. Too many years ago to remember.
And then I also thought of a writing tip post I wrote for The Ink Well about Author Intrusion, although you turn that rule on its head, as it's not done accidentally but very intentionally, and well.