On this day (November 25th) in 2005 UNESCO declared the keris a "Masterpiece of the Oral and Intangible Heritage of Humanity". Because of that many people in the collecting community are deeming this to be International Keris Day. Though i am unaware of any official designation it would seem as good a day as any for that claim.
Well, i'm willing to go along with this if everyone else is. Though personally i like to think of every day as being Keris Day in my world.