I've known for all of my life that I was related to author (and Charlie Chan creator) Earl Derr Biggers, but I was in my thirties before I discovered that Biggers and I shared the same birthday: August 26th. Now I've discovered more coincidences. There is some dispute over Biggers' year of birth--some sites list it as 1884, some as 1885 (for what it's worth, the family records have indicated 1885 as the correct year). It turns out that he and I suffered our heart attacks on the exact same day of the month as well--and if the year 1885 is the correct year of birth for EDB, then we were both exactly the same age when we suffered our heart attacks.
(Thankfully, my heart attack ended up being less fatal than his...)