For those interested in volunteering, Hospitalito Atitlán (http://www.hospitalitoati...) is a great place to help out. The current Hospitalito functions out of a converted hostal, offering medical help to the local communities around the lake. Hospitalito Atitlán's new location is under construction a few minutes down the road, with the first floor scheduled to be completed in November 2010. The volunteer services can range from medical volunteers, cabinet makers, computer assistance, MBA students, volunteer groups for construction, and much more.
The Spanish schools around the lake also provide volunteer opportunities built into the school. EntreMundos (http://www.entremundos.or...), an NGO based out of Quetzaltenango, serves the purpose of connecting nonprofit organizations and volunteers throughout Guatemala.
Climb San Pedro, the large volcano west of Santiago. Do NOT use a guide from Santiago, take a lancha over to San Pedro first and find a guide there many are bilingual. Climbing from the Santiago side is very long and dangerous, the San Pedro side has a developed trail with stairs and handholds in steep parts although there is an entrance fee.
