Believe it or not this is a fully-functioning camcorder, recording on removable Micro SD cards. It's called the Vehu Muvi Pro Micro DV, and I bought mine at Amazon.com for just $65.24, including sales tax, shipped free.
This is the more expensive one. There's one that's $10 cheaper, but it comes with a 2 GB card instead of a 4 GB card and isn't sound activated. The more expensive one is well worth the difference.
Just think of what you can use it for.
[1] Put it in your buttonhole and it's virtually unnoticeable. You could video what the performance looks like from the band.
[2] Since it can be noise activated, stand it on the bird feeding stand and record the birds close up.
Or even skunks, squirrels, etc.
[3] Use it as part of your security system. If someone breaks your door down and you have this trained on the door you will record the burglar.
[4] Put it on the dashboard of your car and record your trip. There are several videos on YouTube shot from the front of cars with this camera.
[5] Put it on a flatcar and push it round your model railroad, to get the view a model person would.
I'm sure you'll think of dozens of other applications, without going into spying on your wife and neighbors, etc.
http://www.youtube.com/watch?v=Z-7anMP0dqU
Here's a sample on YouTube taken underwater. (The waterproof housing is extra, but not very much.)
(Brookes)