MtGox disabled trading today, 25th Feb, at 2am GMT.

I initially saw that there were no price changes and then realized that there are also no changes in the order books.

I then tried to do a test trade and the result was the message "Trading has been disabled": http://i.imgur.com/o7KKjrM.png
I haven't taken this screenshot, but it looks exactly like what I see on MtGox when I try to submit an order.