My father passed away 19 years ago, yet I still pay homage to him every November 27, just 22 days after the anniversary of his death, which I not so much celebrate but mourn. As a member of the DDC - Dead Dads Club - I've healed and feel comfortable making awkward jokes about my loss. I'm fairly certain my Nana and aunt (his mother and sister) continue to gift his grave with fresh flowers every November 27, too.
Is it odd to celebrate birthdays of the dead? Feed me more examples, please.