Rcvd: August 31, 2013
I sent a very nice letter to cinematographer Hoyte Van Hoytema (Lat den ratte komma in, The Fighter) via the "Interstellar" production office in Canada. Included a SAE, IRC, and an index card.
Received the envelope and index card back signed today with a very nice message. Pretty quick turnaround too.

And before anyone asks about the "Interstellar" address, it's easy to find. And I have not received any other replies back from that office.