Somebody notice that we went way past the $500 on MTGox?
Or is my internet playing up again

Yes, every other exchange is following... BTC-e is currently at $460 which is really good for arbitrage...
Go ahead, sell your Bitcoins on Gox, transfer the fiat to BTC-e and take the ARB.
Hint: There is no such thing as a free lunch.
Incidentally, does anyone know what's going on at Gox? Where is the trading volume coming from, considering that you can't get money in or out? All mad bots trading with themselves?
can get money in or out.