Periodically I have found when using Lion, every now and then the Mac seems to freeze and hang up, I am stuck with the beachball spinning and nothing seems to respond. This only seems to happen on my iMac not on the Macbook pro.
Well one quick simple fix that works a lot of the time for me is to press the volume buttons on the keyboard. I just press the Volume up a couple of times followed by pressing Volume down, and this brings it back to life.
When ever this happens I like to reboot the computer to ensure everything is clean before I carry on working.
In relation to this you can get your machine to automatically reboot once it freezes.
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