I think WWOOF-ing is my favorite way to travel. You get to stay with local people (and occasionally other traveling WWOOF-ers) and dive into and learn about the host culture. I always enjoy spending time with people and being useful, and I adore the outdoors, so this program is perfect for me.
The hosts will often place a great deal of trust in the WWOOF-ers that they host, and I was fortunate enough to live in a yurt next to a reconstructed 16th-century home in Wales, work in the garden, chase sheep around, and help with the transport and reconstruction of historical houses for an archaeological company! All of this took place in a gorgeous patch of farmland in central Wales in the company of people from Wales, France, Scotland, Singapore, Taiwan, and England.