"O Americano, Outra Vez!" means "The American, once again!" in Portuguese, which is what one of the samba school boss exclaimed when Feynman was not playing well his instrument, the frigideira, during a rehearsal.
Feynman really enjoyed Brazil's (and notably Rio's) stereotypical "take it easy and enjoy life" attitude.
Key quote that names the chapter:
My friend Matt Sands was once going to write a book to be called Alfred Nobel's Other Mistake.
A friend of mine who's a rich man - he invented some kind of simple digital switch - tells me about these people who contribute money to make prizes or give lectures: "You always look at them carefully to find out what crookery they're trying to absolve their conscience of."
TODO who was he talking about? Robert Noyce or Gordon Moore feel likely candidates: