So it turns out that people who are born on Christmas day are a lot like the proverbial London Bus. Before this week I did not know a single one, and then suddenly I met 3 in as many days (plus someone else who was born at 2 minutes to midnight on Christmas eve). Two of the three were also twins, which is even more bizarre.
Aside from the obvious reason I'm not sure why so few people seem to be born on the 25th of December, it's 1 day in 365 (unless you're born on a leap year - and incidentally I'm yet to meet anyone born on the 29th of February) so maybe I've just been unlucky.
There's also that weird fact that according to probability you only need 23 people in a room for 50% chance that 2 of them will share a birthday, and approximately 70 people for a 100% chance. I only have seven cousins but I share a birthday with one of them.
For a while facebook used to have a page where you could see all of your friends in birthday order. At the time I knew approximately 400 people on facebook but they only covered about 220 days, with September the most popular month to be born in and February the least. By carrying it on for a while I was able to tick off another 50 days, but only now could I put a mark (or three) next to December 25th!