Srila Prabhupada left this world on November 14, 1977, in Vrndavana, India. Devotees observe this anniversary with personal remembrances of Srila Prabhupada, readings from his biography, and so on. Devotees also fast until noon and then eat food that has been symbolically offered to Him.
This year, the Krishna conscious world revisits Prabhupada's departure from this world on 17th November 2012. The main concept is that Prabhupada as a spiritual entity is very much alive, so there is no reason to mourn. Just revisit, pay respect and reflect. The following documentary on Prabhupada sheds some light about his vision, life and work. It is called Prabhupada the Perfect Example of Everything He Preached (Part 1).