Apollo 11 landed on the moon July 20, 1969, the culmination of President John Kennedy's challenge to get there by the end of the decade. Anyone who was old enough at the time remembers where they were that day.
Here are a few links to web pages and articles published in honor of the 40th anniversary of that epic mission:
NASA Apollo 11 pages
Smithsonian Air & Space Museum, Apollo 11 pages
40 years after Apollo 11: Those who were there relive the worry and glory (Houston Chronicle)
The Guardian (UK) page remembering the moon landing
Apollo 11's Bright Glare (Washington Post)
Apollo astronauts bemoan state of US space program (Reuters)