Yoko Ono has taken out a full page ad that is running in today's New York Times, which you can find in the back of the Week in Review section. The ad (above) asks that December 8th, the day that John Lennon was killed, become a day of healing and helping others. She writes:
"Every year, let's make December 8th the day to ask for forgiveness from those who suffered the insufferable. Let's wish strongly that one day we will be able to say that we healed ourselves, and by healing ourselves, we healed the world."
In March of 2003, Ono took out full page ads in major newspapers urging the US not to go to war. They read "Imagine Peace...Spring 2003". And of course, in the winter of 1969 Lennon and Ono had their "War is Over! If You Want It" billboard in Times Square (which Ono recreated in 1998/99).