Renting a bicycle or motorbike to ride around the countryside seems to be the most popular activity. You can easily create an itinerary to include visits to the nearby waterfalls and hill tribe villages. Potential day trips include the Tham Lod bat cave 55 km away in Pangmapha, best visited when the bats emerge just before sunset.
Go off-road through the mountains of Pai on a off-road motorbike tour. Better off-road possibilities and better prices than in Chiang Mai. Ask your guest house where to book.