Mobile Ad-Hoc Network MANET
From the Wikipedia at http://en.wikipedia.org/wiki/Mobile_ad-hoc_network
"A mobile ad-hoc network (MANet) is a kind of wireless ad-hoc network, and is a self-configuring network of mobile routers (and associated hosts) connected by wireless links – the union of which form an arbitrary topology. The routers are free to move randomly and organize themselves arbitrarily; thus, the network's wireless topology may change rapidly and unpredictably. Such a network may operate in a standalone fashion, or may be connected to the larger Internet.
Mobile ad hoc networks became a popular subject for research as laptops and 802.11/Wi-Fi wireless networking became widespread in the mid to late 1990s. Many of the academic papers evaluate protocols and abilities assuming varying degrees of mobility within a bounded space, usually with all nodes within a few hops of each other, and usually with nodes sending data at a constant rate. Different protocols are then evaluated based on the packet drop rate, the overhead introduced by the routing protocol, and other measures.
The Children's Machine One Laptop per Child program hopes to develop a cheap laptop for mass distribution (>1 million at a time) to developing countries for education. The laptops will use ad hoc wireless mesh networking to develop their own communications network out of the box." (http://en.wikipedia.org/wiki/Mobile_ad-hoc_network)
open / free communities developing ad hoc multi hop wireless networks :
such as in Brussels ( and some other cities in belgium ) : http://reseaucitoyen.be/
in germany : http://start.freifunk.net/
and other communities all over the world : http://global.freifunk.net/