Back in 1969, some pranksters at NASA inserted scanned images of three Playboy centerfolds (on fireproof plastic paper!) into the little checklists the Apollo 12 astronauts took into space.
[Apollo 12 crew member Pete] Conrad got Miss September 1967 Angela Dorian ("Seen any interesting hills and valleys?") and Miss October 1967 Reagan Wilson ("Preferred tether partner"). [Al] Bean got Miss December 1969 Cynthia Myers ("Don't forget – Describe the protuberances") and Miss January 1969 Leslie Bianchini ("Survey – her activity").Link to Playboy.com blog entry, and there's more background here at NASA.gov: Link. (via newsonthemarch)
Conrad told us in 1994: "I had no idea they were with us. It wasn't until we actually got out on the lunar surface and were well into our first moon walk that I found them." Bean recalled: "It was about two and a half hours into the extravehicular activity. I flipped the page over and there she was. I hopped over to where Pete was and showed him mine, and he showed me his."