When an app freezes on my app, I will press Command ⌘+Option ⌥+Esc ⎋ to open the Force Quit window.
However, this will take minutes often, and clicking on the Force Quit button freezes the Force Quit window and makes the beach ball show; the sheet confirming the force quit only shows once the application unfreezes.
Also, if I right-click the Dock icon while the app is freezing, then the Dock will freeze, but it doesn't freeze when I just hover over the icon.
It is also possible to move the application's windows.
So how come it possible for some things to be not frozen, while the most important thing (the Force Quit window) freezes at any interaction? And what do you do when the Force Quit window itself freezes?

ps? I have an issue similar to Jonathan's, but the Force Quit window appears to be perma-stuck open (I can ssh into my machine) – keflavich Jul 25 '12 at 20:38