Dear Mr. Skilling,         Thank you very much for taking the time to meet with me today.
Joannie told me how extremely busy your schedule is, and I feel honored that you were willing to spare some of your time to get to know one of your interns;  it really says a lot.
Best of wishes to you and your brother, and I hope that we get a chance to meet again...next year!
Sincerely,

Thank You