Dominions 3 and multiple rigs: [Gaming in Person]

[Archonsod]

If you only want to run older ethernet you can build a bus network without a hub. I don't think you need a hub for a firewire network either, but you would need to make sure all of the PC's have firewire ports.

You don't need a router unless your looking to share an internet connection (or you want to subdivide the network, but that would be silly...). You can probably pick up a cheap hub for pennnies. Configuration is as simple as plugging the PC's into the hub. You won't need to worry about anything else unless you want to share files across the network. The only other thing which might be a problem are firewalls, but most should let you specify permissions by email address (if the network isn't connected to the net, you could simply turn off the firewalls).