I was born 2 days after my mums birthday, she went into labour on her birthday. My DS was born 2 days after my birthday and I went into labour on my birthday too. Came out of hospital 4 days later on his dads birthday!
My cousins baby was born 2 days afetr DS who incidently was due on his dads cousins birthday.
Mt other cousins DD was born on his birthday, my other cousins dd is 2 days later.
My other cousins dd was born 3 days before DS so the dc's in this generation are all 3 days apart in this month. (my cousin whos dd was born to fit the aug pattern was due in dec when the other 2 were born)
Whats even more amusing is that from 1978 until 1990 my mum and her sisters each had a baby in each of the years. Then we became sporadic until we started having babies and started a new pattern. 
Oh have a cousin born xmas day too.
3 on same day on different years tho - hope these parents do the lottery.