Wittgenstein and Housman:
This story is in a letter from Guy Davenport to Marjorie Perloff; the letter is worth reading in full, it cleverly juxtaposes Wittgenstein with Gertrude Stein, who might have liked the implied comparison. Davenport also has amusing things to say about Wittgenstein elsewhere; see a prev. post.
While on the topic of celebrity letters, I should link to Eliot's letter to Woolf that was posted on the Paris Review's blog today. And, while I'm free-associating on this topic, to Eliot's magnificent letter to Middleton Murry on his second (third?) marriage.
PS re title see here.