When X and GNOME are working normally, I can just hit Ctrl-Alt-F2 to leave GNOME and use the terminal on the second virtual console. To switch back to GNOME, I can just hit Alt-F1.
Today, X or GNOME stopped working normally for me and I was unable to get to a virtual console. I was still able to move my mouse cursor around but I wasn't able to click anything. As far as I could tell, my keyboard was unresponsive, but maybe the right keyboard shortcut would have helped. I ended up pressing the power button on the computer to gracefully shut it down, but what could I have done to avoid this?
I'm using CentOS 6.0 and GNOME 2.28.