From the Earth to the Moon Season 1 Episode 4

Michael Collins (CapCom): I've just been informed that your accuracy at navigation has reached the theoretical limits of our system.
Jim Lovell: Well, that's very flattering, Mike.
Michael Collins (CapCom): Best guess is you must be cheating somehow.
Jim Lovell: Aw, Mike, you caught me. I came up here by myself last week to practice.

Frank Borman: (about the emergency evacuation procedure) Let me see if I've got this. It takes 20 seconds to open this hatch. That's you, standing upright on the factory floor. This is me, strapped into the side of the spacecraft. Everything's upside down above me and behind me. Something goes wrong, I don't want to have to look at a checklist. I can't wait 20 seconds to evac. Something's got to open that hatch in a heartbeat.

Jim Lovell: (looking at the Earth from orbit) If I were a lonely traveler from some other planet, what woud I think about the Earth from this altitude. What I'm curious about is whether I'd land on the blue or brown part of the Earth.
Frank Borman: Better hope we land on the blue part.

Frank Borman: Houston, this is Apollo 8, we are in lunar orbit.

Frank Borman: Houston, Apollo 8. Please be advised there is a Santa Claus.

Chris Kraft: (after learning that Borman vomited in the space craft) Man, it's got to smell bad up there!