A tiny video camera called the looks at first like your standard extreme sports helmet cam. But in addition to doing neat tricks like streaming live video to Facebook and other services, the Looxcie HD does something truly amazing.

You can press a button, and it records constantly for up to five hours. It erases the video it captures almost as fast as it records it. However, if something happens that you wanted to record, just press another button, and the recent video is saved and uploaded to the cloud.

So the default in this mode is to constantly record and erase. It ends up being a video camera not for shooting video in the present, but in the past.

The Looxcie HD camera borrows the record-and-purge concept from consumer dashcams -- special cameras designed to record video from inside a car constantly, and delete it constantly unless the user pushes a button that saves recent video.