I've mentioned before that my school has a really stupid network policy -- they give every computer a static IP rather than assigning them through DHCP. Presumably this is so they can trace things. Guess somebody never heard of a MAC address.
Here's what I learned while attaching my laptop to the network: not only are the addresses staticly assigned, they are all internet addresses. Not local network, not behind a firewall, internet addresses. I was speechless. Still am, kinda.