Yeah, it's weird. I got it too.

wtf is it? is it an issue with the version or a problem with bukkit?

Are you connecting with mc.minetown.net ?

Personally theory: Minecraft.net may be having issues with their servers, and these errors may be resulting from a mis connection to the MineTown servers, etc. Whenever I log off my client, and back in, it works fine.

i still cant connect even with mc.minetown.net, ive forced updated 12 times now and i can not connect still!, its killing me i tell ya!

Use a clean Client, There are some mods that will prevent you from loggin on.

still wont work, ive deleted my whole .minecraft file then force updated it and i cant get on... mabey its my HP, or my internet...

looks like all i can do now is stare at a wall and wait for this nightmare to end

This has been happening to me all day as well :C I can still get onto other servers but I need my Minetown back </3

mee too </3