There are some opportunities to volunteer while you are here. Teaching English and computers are most common options. Go to the organized meetings of one of the organizations and don't accept requests to privately tutor monks that address you on the streets; some of them will ask you to be their sponsor after a few days and many already have a few 'sponsors'. Do not expect any gratitude for teaching English for free. Chances are your students, on top of your professional effort, will request you to give them (large quantities of) money, plane tickets, visa and passports. Monks in robes, without robes, ex-monks and other men will pursue you and propose marriage. They don't like us, but want a meal and plane ticket and a green card.