My Dad is Red/Green colour blind and there are some quite odd things about it.
1. Its almost exclusively male. Except in rare scenarios.
2. Its exclusivley hereditary although through the maternal line. I.E. My Dad is colour blind but neither me or my brothers are. However my sisters 2 youngest sons are both colour blind. (It also seems to skip the first son of any woman who is a maternal link)
3. If a Colour blind man and a woman whos father was colour blind have children then all of their children can be colour blind.
My Grandfather owned a woolen mill and his head of stores was completely colour blind (much more rare) however he was the best person to judge shades of similar colours as he had the best shade perception of anyone. He also kept the best logs so he wouldnt be confused.
Oh, but the best thing about having a colour blind dad is playing him at snooker and taking 4 points everytime he pots the brown instead of a red.