Caroline posted this and I wanted to share it as well. A letter from Barack to his kids, with a great snippet:

I hope both of you will take up that work, righting the wrongs that you see and working to give others the chances you've had. Not just because you have an obligation to give something back to this country that has given our family so much—although you do have that obligation. But because you have an obligation to yourself. Because it is only when you hitch your wagon to something larger than yourself that you will realize your true potential."

Read the whole letter.