Not in my family, but I know three pairs of twins and a set of triplets.
First twin set: Boys, different hairlines but still look similar, both into politics, one is a heck of a lot more chatty and the other one is a lot more quiet.
Second twin set: Girls, almost look identical but slightly different chins. At first glance it looks like they have all the same interests but it branches off into different directions like one is into more gore horror and the other one loves Japanese type creepy horror. The both have strong personalities, but it's like they take turns being the more aggressive one.
Third twin set: Boys, mirror identical, both quiet, the same style of clothes, and I never feel safe calling them by name because different hair cuts are the only way you can tell them apart. It was easy back in high school when one of them lost weight, but the other dieted the next year and it was back to 'I have no idea which one I'm talking to'.
The triplets: 2 boys, a girl, extremely different personalities, different hair colors, and they look nothing alike which is why it never dawned on me they were triplets until I found out their birthdays.