1. July 28, 1964. It's the launch day of the Ranger 7 lunar impactor. The 6 spacecrafts prior to this launch had failed, so everyone was pretty worked up.
  2. Dick Wallace, a mission trajectory engineering, handed out peanuts to try to reduce stress levels.
  3. The mission was a success and now whenever there is a launch or difficult maneuver the lucky peanuts are handed out.
  4. This tradition is taken so seriously that if you have a peanut allergy apparently you are sent to another room.
    I was told this when someone from NASA came and spoke about some of the JPL missions at my university.