(Note: email address is triple protected from spammers.)
Few primary and high schools in the remote hills of Nepal are looking for volunteer Math. or English teachers in exchange for room and food. Classes (45 minutes) 3-4 a day with @15-40 students per class.
There are solar powered electricity and internet connection is through mobile sim card. you can get a 3 month tourist visa on arrival to start with. The school does not pay for the visa expense.