Looks like one of the server people were eating doughnuts and didn't notice. Getting the same problem
I can ping the server and access the live map, Seems like an actual problem with the Minecraft server itself.
There is something going on, we are tracking it and working on it, for those that are stuck connected to SMP8, I am sorry but you will be stuck there until we can force a restart on the server (just waiting on response from aikar at this point).
Ahhh! Aikar's doing is evil work now! Starting with SMP8, people cant join others and SMP8's economy is gone! Run for you Minecraft Life!