The Ipod instructions tell you that in such a case, you should simultaneously press down the MENU and PLAY buttons, but I'm here to tell you, true believers, that that is in fact wrong. It does absolutely nothing, at least on mine. The buttons you should press are in fact MENU and the round one in the center (which has no name and therefore frustrates my plan to put the name in all caps).
And so, the ipod unfroze and I was able to finish the book. Then we ate pork chops.