My bil has brown eyes and my sis has bright blue eyes. My niece has brown eyes and dark hair and my nephew has blue eyes and is blonde! My niece also has an olive type skin - neither parents do.
I also have a friend who is blonde and blue eyed, she has two brothers, one is ginger with blue eyes and the other is dark hair and brown eyes. Both parents have blue eyes, her mum is brunette and dad is ginger. All the siblings look alike, just different colourings!
As far as I was aware - genes can be a kick back from later generations. I read a story in a magazine once about twins, one was white and the other was black and both parents were white. They traced back family trees and found in his side a black relative a good few generations back and it had passed the gene through.
Stranger things have happened!!