One of the first things I thought when I saw the iMac would have a built in isight camera was "the doors have ears and the walls have eyes." If you really want to invite big brother into your home (or be him yourself), you can set your iMac or Macbook to spy on your home and the other users of your computer.

Turn on fast user switching in the Accounts System Preferences panel, set up a few users with passwords, then open a new movie recording in QuickTime Pro. Pretty basic and a no-brainer -- keeping the user logged in who has the QuickTime movie recording will record continuously through any fast user switching.

Set the machine not to sleep, but just to turn off the screen, and your computer will look like it's off while it's filming and recording the audio in the room. Other than the little green light, it works perfectly ... now who out there knows how to politely ask your Mac to turn off that light?

[robg adds: I was intrigued to find that the recording does, indeed, keep right on working after fast user switching. And you don't need a new Mac to try this, just any Mac with QT Pro and a recordable video source. Keep in mind that you'll chew up a lot of drive space doing this -- about 13MB per minute, based on a quick test with my iSight -- so an hour of video would be 780MB. You can use QuickTime Pro to export a finished movie in a more compressed format, of course, and then remove the original.

If you're really interested in something like this, EvoCam is probably a better solution. You'll lose some frames per second, but you get much better recording options, and you can use any web browser to view the image in real time.]