This might sound morbid to some of you, but I assure you it is not.
For the last 8 years, my immediate family has celebrated my grandfather on the day he passed away (death day). Or more affectionately known as "Grandfather's D-Day Party."
We have a big dinner with all the foods that remind us of him. Fried chicken, macaroni and cheese, cheetos, canteloupe, watermelon, diet Dr. Pepper, Fresca, etc. (Yes, we usually have tummy aches the next day.) While we eat, we go around and share funny/sweet memories of Grandfather (or for the in-laws, memories of their own grandfathers). And it is not uncommon that we are all laughing so hard we can't talk for 5 minutes. After dinner we have the traditional screaming contest (usually won by my dad) followed by Grandfather's favorite movie, The Music Man.
I look forward to, and enjoy, this party more than most other holidays we celebrate. Yay for Grandfather! He was tough as a boot!