TOUR GUIDE: …and on this spot, the Magna Carta was signed!
TOURIST: When was that?
TOUR GUIDE: 1215.
TOURIST: Oh, darn - we missed it by twenty minutes!
Psychiatrist to soldier: “So, when did you last have sex?”
Soldier: “Err, about 2020.”
Psychiatrist: “That’s a long time ago.”
Soldier, looking at his watch: “Not really. It’s only 2045 now.”