My cause of death. Tombstones would be far more interesting if they had that on them. If they're cool enough of course. Part of my run goes through a cemetary and there is one tombstone there for a guy who's name i can't remember but right below his name and dates is "Eaten by a Shark". Bam.
Or I'd go the Spike Milligan route and make a joke at my own expense. Can you believe they made him have "I told you I was ill" in gaelic because they felt the joke was unfitting for a cemetary? This is Spike fucking Milligan here, you allow him to do his thing wherever and whenever he wants, including when he's dead.