If you've got a sneaking suspicion that your boss/girlfriend/mom has been less than honest with you, there are plenty of ways to sneak a look at their activities without them ever knowing. If you think what they do on the computer might just reveal the truth behind their shady behaviors, this Covert Keylogger Keyboard will give you all the data you need.

This little privacy-invading gem has 2 MB of onboard storage, enough to record up to 2 million keystrokes. That'll cover enough to let you see just what was typed over several days of use, picking up passwords, e-mails, and IMs for you to sift through. Sure, you'll feel justifiably dirty invading someone's privacy so blatantly, but hey… uh, well, I guess there's really no excuse. It's a good thing this thing's prohibitively expensive at $435, otherwise scumbags like you might actually buy one.
— Adam Frucci

Product Page, via The Red Ferret Journal