Response code 503?
Edit: Oh right, restarted the application and yeah, won't connect to minecraft.net
The 503 error is because (I think) minecraft.net is down, and the server verifies your user name with minecraft.net to make sure you're not pretending to be someone on the whitelist.
I shall turn off that check now and you should be able to log in if you do 'play off line' when you load minecraft.
If you still can't log in, the new launcher (which uses HTTPS) seems to still be working. Can grab it here:
https://s3.amazonaws.com/MinecraftDownload/tmp/MinecraftLauncher.jar
That is the beta/leaked one that Notch linked to on Twitter on Friday.
The 'official' one came out today, just before minecraft.net fell over :D
I apologise for ruining the linearness of the tunnel track, but run away carts should now be collected whichever track they are on and whichever direction they are travelling.
There's even a minecart dispenser which may or may not work.
Fuck no. (Maybe). At the moment it's aiming to join up with the big road which leads off Kos's giant bridge. After that, who knows?
Just realised, though, that it's probably going to run into all kinds of underground stuff near the old spawn. Hope no-one minds it just running straight through everything.