Yoo Hoo!
Neighbornode.net is exactly what i’ve been waiting/thinking of for the last few months. I’ve noticed, I know, but don’t really know the people who live on the other floors of my apartment building.

This software allows you to have a wi-fi hotspot and bulletin board/wiki setup all-in-one.
And you get to keep your own firewall, independent connection, etc too.

Check out their site for more info.