I started my iPad this morning and went away to something. When I came back the screen was black, not so unusual. What was unusual was that nothing happened when I pressed the power button (or whatever it is called). Eventually, I held down the power and home buttons for quite a while and the iPad re-booted. The Apple icon displayed for quite some time before things got back to normal. Does anyone know what this is all about? I noticed, as an aside, that re-booting doesn't clear the task list.