When is the last time you talked with your father? Or, for that matter, with that man in your life who was a father to you at an important time in your life? With each such man in your life, consider a conversation with him this weekend of Dad's Day. If he has died, talk with him anyway, the kind of private conversation in which you say thank you for the things he said, the things he did to support you when you needed it, and in which you forgive him for the ways in which he disappointed you.
And for each such man who is still alive, consider in intimating the same conversation. He will be thrilled. You may likely not have had many talks in which he felt your hero in some way...this can be your opportunity to let him know how he was that and more.
And if you are yourself a Dad, consider the conversations you look forward to having "someday" with your son or daughter. No time like the present.
Let each of your children know what importance they play in your life. Tell them how proud you are of them and how much you want to help them become that person they wish to be (not necessarily the same as the person you wish they would be!). Ask them to tell you three ways you can be a better Dad to them.
Whatever their response, I predict you will be surprised.