"House for everyone" - it is a project made by treveler Anton Krotov (Russia) but now a lot of other travelers make own houses every year. One traveler as organizator spend his money for house or apartement and other travelers (hitchhikers) can stay there for free (or donation if they want). Usually houses like this exist only few months but at the same time might be a lot of houses in different places and you can choose where to go. Rules: No alcohol, no narkotics, no smoking inside.
You can find all the houses here: https://vk.com/topic-1398178_24870655?post=5691 Just translate it with Google Translate or other.