I think I recognize the guy on the right from a Monty Python sketch.
He does bear a striking resemblance to John Cleese and the guy to the immediate left could be Eric Idle. I'm positive that the guy on the top is Billy Dee Williams in his Lando Calrissian costume. And, the guy on the bottom could be Harry Potter, or George Stephenopolous.
GOD: Arthur! Arthur, King of the Britons! Oh, don’t grovel! If
there’s one thing I can’t stand, it’s people groveling.
ARTHUR: Sorry—
GOD: And don’t apologize. Every time I try to talk to someone it’s
“sorry this” and “forgive me that” and “I’m not worthy”. What are you
doing now!?
ARTHUR: I’m averting my eyes, oh Lord.
GOD: Well, don’t. It’s like those miserable Psalms— they’re so
depressing. Now knock it off!
ARTHUR: Yes, Lord.
GOD: Right! Arthur, King of the Britons — your Knights of the Round
Table shall have a task to make them an example in these dark times.
ARTHUR: Good idea, oh Lord!
GOD: ‘Course it’s a good idea! Behold! Arthur, this is the Holy
Grail. Look well, Arthur, for it is your sacred task to seek
this Grail. That is your purpose, Arthur — the Quest for the
Holy Grail.
ARTHUR: A blessing!
LAUNCELOT: A blessing from the Lord!
GALAHAD: God be praised!