Red Letter Day Share definition Flag A Red Letter Day is when a scientist gets teleported to a different place, and it FAILS! "That's right, Barney. This is a red letter day. We'll inaugurate the new teleport with a double transmission!" -Dr. Kleiner Red Letter Day by OfficialDaft February 14, 2025 0 0 Get merch Get the Red Letter Day mug. Buy Now — $32.95 See more merch