How do people join servers with Minecraft down?

Minecraft website and server sessions are down for maintenance *cough* bull *cough*. People still seem to join and leave servers as usual. How are they doing this when sessions are down? Xpaw.ru/mcstatus

AFAIK, some servers are not run my Minecraft themselves. I have a mate who runs a server off an extra computer laying around. In essence, I'm connecting to his computer and his server is up. There's no correlation between Minecraft and his server.