Kontiki is one of two annual scouting events in South Africa- the Gauteng provincial event is the biggest annual scouting event in the country.
Kontiki takes it's name from Thor Heyerdahl's 1947 expedition to sail from South America to Polynesia to prove that it was possible for Polynesia to be colonized from the East, rather than from the North via Asia as most people thought (and still think). Read the book or watch the DVD to find out more.
If you are thinking of building a raft with your scouts, the Cape Western and Gauteng Kontiki websites have quite a few tips for you (you will need to sign in to the Gauteng site to download the booklet, but it's worth a few minutes spent filling in the form). I'll be posting more about rafts in the next couple of weeks, including some conventional and also rather unconventional raft designs and some tips for designing your own.