GREYCELL #2

 

As a 17-year-old high school junior, this person found himself in need of a class project. His proposed idea was initially turned down by the teacher. He went ahead and finished his project, receiving a B minus for his efforts. His teacher compromised and promised to deliver a better classroom grade if he could get the U.S. Congress to accept his idea. Needless to say, they did. Since then, he's been in all 50 states and 37 foreign countries, making hundreds of speeches and traveling more than 100,000 miles a year. He also has been the guest of nine U.S. presidents at the White House. Identify him.