A school network technician mentioned open-mesh routers a while ago, and I was impressed with the claims (and the price) of the technology. I recently bought three of these mini-routers, and I'm very impressed. They're small, pretty cheap, and do very cool things.
Like any other wireless router, they connect via ethernet to your modem and act as a wifi access point for wireless network access, but they have some extra cool features. As the website name implies, they can operate in a mesh configuration, which is something I first heard about with the OLCP XO laptop. So you can plug one router into your modem, and as long as the others are close enough they connect to it wirelessly and repeat the signal both wirelessly and over their ethernet port. Very cool.
Other features that I appreciate in these routers are that they support two SSIDs (so that you can have one public and one private if you'd like), the antenna is replacable (e.g. with a higher gain antenna), and I like they way that they've implemented the online dashboard for changing settings across all routers in the mesh.
All in all, I like these gadgets. Great wireless routers, especially for getting wireless Internet access across a fairly large area.