Ubiquitous Internet, an idea explained to me a few times, has given me a much, much crazier one.
Across the earth, we bury routing boxes, which connect to the nearest city's power supply. We connect each of these boxes to its four immediate neighbors with fiber optic cable. Let's say there's one box every 1000 feet in every direction. Let's also say that each one is ready to accept a cable from the surface.
If these boxes can route TCP/IP, then connecting any two boxes to computers on the surface will allow them to use the internet as it was originally designed -- they can chose any of an infinite number of routes to reach each other, and can route around any problems that occur in the network. If the surface connection to these boxes is a WiFi node, then people within the radius of the WiFi signal, a sphere whose radius is about 35 meters, would get internet access from that node. Of course, WiFi nodes can also use each other, allowing a mesh network to develop around that node.
If a city built many WiFi nodes, one of which tapped one of these boxes, then that city would have Ubiquitous Internet. Anyone with a laptop would be able to access the Internet from anywhere in the city. Any device able to use WiFi and TCP/IP could communicate anywhere in the world.
Or, alternatively, ISPs could connect to the internet from one of these boxes. Backbone sites, which require high bandwidth and are difficult to maintain, would be unnessesary, as now the underground box-grid would be the backbone. If an ISP connected to multiple boxes, it would be incredibly difficult to disconnect from the internet. If the ISP had multiple sites that each connected to multiple boxes, it would be impossible to disconnect.
There are some worries about spam, but I think technological solutions to spam are not the answer. Law is. Spam should be banned by law, and those that break that law should lose their assets to pay for things like the underground box-grid.