This is an interesting piece of open source software produced by Alexandre Dulaunoy who can be reached at (a at foo dot be).
Forban is a kind of p2p application for link-local and local area networks. Forban works independently from the Internet and uses only local area capabilities to announce, discover, search or share files. Forban relies on HTTP and it is opportunistic (meaning replicating any files seen in its proximity or interest). The name took its origins from an old French word (a forban is a kind of pirate). “Forban” the pirate can be also a play of words in English at a time where government or corporations want to limit or ban access to the Internet.
The current implementation is written in Python. The Forban protocols are minimalistic to ease the accessibility to build independent Forban in any decent language or even in shell scripts (using tcpdump and wget for example).
Forban operates in different modes, the opportunistic mode is the default and it also works as a gossip protocol to disseminate data with any other Forban implementation in its proximity. The main concept is to provide persistence for the disseminated data, even for periodic or unreliable bits of communication.
More information at http://www.foo.be/forban/