“A deathday party?” said Hermione keenly when Harry joined her and Ron in the common room. “I bet there aren’t many living people who can say they’ve been to one of those — it’ll be fascinating!”
“Why would anyone want to celebrate the day they died?” said Ron, who was halfway through his Potions homework and grumpy. “Sounds dead depressing to me...”

Harry Potter and the Chamber of Secrets - Chapter 8 : The Deathday Party
See this quote in the Pensive -