I can't say I know of any other Americans who went to the streets of Rio in the mid-1950s and played samba in the streets with locals. Clearly, this guy was a genius and ahead of his time. But what's amazing is he also happened to be one of the greatest physicists of all time, a Nobel winner and beloved professor.
For sambistas, it's interesting to note that he found pandeiro tough and settled on frigideira -- an instrument that doesn't get enough love nowadays!
Here he is on the subject of samba carioca:
http://buoy.antville.org/stories/1466743/
And here's a brief overview of his other accomplishments:
https://www.youtube.com/watch?v=JIJw3OLB9sI