Certainly, institutions that benefit from hundreds of hours of volunteer help, such as the Cleveland Museum of Art , can attest to the importance of volunteers. Studies now show that the volunteers themselves also reap advantages, including expanding their social networks, building their resumes, enjoying healthier lifestyles, and traveling the world.
Museum volunteers working at Parade the Circle
A study  led by Peggy Thoits, former sociology professor at Vanderbilt University, examined how volunteering affected various aspects of well-being and found that “people who were in better physical and mental health were more likely to volunteer, and conversely that volunteer work was good for both mental and physical health. People of all ages who volunteered were happier and experienced better physical health and less depression.” Reaping those benefits is becoming easier with the ever-broadening range of volunteer opportunities that exist today. A 2011 Australian government report  summarized that the hottest trends in volunteering included participating in short-term or project-based volunteer roles, combining travel and work with volunteering, and volunteering in roles that require involvement only online and not in person or at a physical location.
Museum volunteer manager Liz Pim and volunteer Marty Trembly
Also, check out the New York Times travel section article  from July 2011 on saving money on vacations through volunteering.