Volunteer for COUCHSURFING

Couchsurfing is a neologism referring to the practice of moving from one friend's house to another, sleeping in whatever spare space is available, floor or couch, generally staying a few days before moving on to the next house.

The company, its website, and the culture of hospitality exchange it is meant to support are all commonly referred to as "Couchsurfing" by the website's userbase, though sometimes the "s" is capitalized.
People who use the Couchsurfing.org website frequently refer to themselves as "couchsurfers", "surfers," or "CSers" for short, demonstrating a mix of loyalty to both the website and the ideals it is thought to support.

Free to register. Members are encouraged to provide information and photos of themselves and of the accommodation they offer, if any. More information provided by a member, and other members, improves the chances that someone will find the member trustworthy enough to be their host or guest. Security is measured in a variety of ways, including member references, verification and the vouching system. Members looking for accommodation can search for hosts using several parameters such as age, location, gender and last login.
Homestays are consensual between the host and guest, and the duration, nature, and terms of the guest's stay are generally worked out in advance. No monetary exchange takes place except sometimes for compensation of incurred expenses (e.g. food). It is common practice for guests to seek non-monetary means to show their appreciation, such as bringing a gift, cooking a meal or teaching a skill.
Couchsurfing provides groups where members may seek travel partners or advice. Members organize activities such as camping trips, bar crawls, meetings, and sporting events.

Members who wish to volunteer for various tasks on the site and help spread the word about Couchsurfing in general can ask the company to be selected as ambassadors. Ambassadors must in theory be role-models and actively promote the "Couchsurfing spirit" among members and to the public and comply with a specific code of conduct and guidelines. In addition to promoting use of the site, they greet new members, help with questions, organize and promote events, serve as emergency contacts for users, and perform other administrative tasks, all on a volunteer basis. Their status as an "ambassador" is indicated by a yellow flag on their profile. While it is a purely volunteer position, it is a status that many ambassadors value.
Source: wikipedia.org