USC has had more Olympians (as well as gold medalists and overall medalists) than any other U.S. college/university. The school has had 396 athletes (prior to the 2012 Olympics) who attended the university before, during or after the time they competed in the Olympic Games.
The most famous in the American Taekwondo Association is the scrolls of songahm. If you want to read it search scrolls of songahm on google.
Micheal phelps has to be the most famous Olympic for having the most medals ever, and getting the most at one Olympic games. Another famous olympic of 2012 is Gaby Douglas who was the first African American to win gold in gymnastics individually and in all around. The Magnificat 7 were also very famous... The list goes on.