The program began in 2002 when South Korea ran out of hotel rooms while hosting the Soccer World Cup. Buddhist temples were asked to open their doors, and when visitors who stayed in them later raved about the experience, Korea tourism officials realized that they had discovered a wonderful new travel program.
Some temples accept only group reservations, but others are open to individuals. See here for a listing.
The basic program at most temples includes Buddhist rituals, Zen meditation, tea ceremonies, and barugongyang (a traditional Buddhist meal). Additional activities may including mountain trekking, lotus lantern making, and rubber stamp making.