The province of Mae Hong Son, in Thailand's far northwest, once had a reputation as "Siam's Siberia"—a place of misty hills and deep valleys as far from Bangkok as it was possible to get. Today the same qualities make Mae Hong Son an ideal destination for whitewater rafting on the Pai River, a swift flowing watercourse swollen by the annual monsoons to provide some excellent sport. Stay in the small and isolated town of Pai, populated by both Thais and local hill tribes. The accommodation is surprisingly good, as is the wide choice of food (for some reason there's an excellent Israeli restaurant!). Rafting facilities are good, and you'll find expert advice as well.