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GeoVisions is an organization which arranges volunteer teaching opportunities around the world. I stumbled across them when reading about a volunteer summer teaching opportunity in Italy. For $1,500 US (plus the cost of flights and some meals), you can spend four to eight weeks in a shared apartment on the Italian beach. In exchange, you agree to provide 20 hours a week of English tutoring at a summer camp.
GeoVisions looks very interesting and they also offer paid placements. You won't get rich at any of them unless you count world experience as riches.