It has been noted that Roger Ebert and Paul McCartney were born on the same day (year, month and day). How many such coincidences should you expect?

To make things specific, assume there are 1000 celebrities of such stature and recency, and that whatever their average age is, the standard deviation of their ages is 12 years and follows a normal distribution. Of course the date is rounded to the day; don't worry about the hours.

Feel free to vary the assumptions for bonus answers.