Since 1976, volunteers with Habitat for Humanity have been helping to build homes for disadvantaged families in the U.S. and around the world. Overwhelmed by the idea of starting from the ground up? A few years ago, Habitat launched a smaller-scale revitalization program called A Brush with Kindness, which involves painting and fixing up existing homes that have fallen into disrepair, often because low-income homeowners have been hit by a hurricane, tornado, job loss or medical emergency.
Calories burned: A whopping 1,720 for a full day of carpentry, installing rain gutters or building fences. 1,432 for a day of painting and weather-stripping.
Muscles worked: Shoulders (be sure to switch arms while painting); back and quads (carrying bags, bricks and wooden beams); heart (walking around the site). Make sure you can squat easily, lift a brick in both hands and carry them for two laps around your house.
Karmic bonus: A shelter becomes a home.