If you are having an odd error when trying to log into a server, just be aware that Minecraft.net is currently experiencing an issue of some sort. I checked the forums and it is pretty widespread so don't think it is EMC. I tried all the EMC servers and 4 others that I sometimes go to and I am still getting the same thing. This may not affect everyone, but it will affect some of us so just be patient and calm.
We already have a thread about it, but thanks for the info for anyone that didn't know. They're back up now