Last year at the local planetarium I saw a great presentation about how the Polynesians navigated using the stars. It was a tradition that was almost lost, but they found someone in the 70s whose grandfather had taught him how, and now they have a school in Hawaii that teaches it.

http://pvs.kcc.hawaii.edu/index/founder_and_teachers/nainoa_...

Interestingly, part of their motivation in reviving it was that they were offended by Heyerdahl's hypothesis, which in their view basically said "Polynesians were dumb enough to get on a raft and just let it drift." More recently DNA analysis has shown that Polynesians came from Asia, not South America.