Require passwords to launch programs with Empathy
Users of XP Pro or Vista Business/Ultimate don't technically need to bother with a program like this. It's fairly easy to use secpol.msc to set up software restrictions on a PC. Empathy, however, will be easier to set up for the average user.
There's nothing to install - just extract the zip file to a folder and run the executable. Browse to the executable you want to protect and enter a password. The unregistered version is limited to a single character, which ought to work fine in a home environment. After all, most people will probably think it's a multi-character password, guess incorrectly, and give up after a few failed attempts.
Empathy is "postcardware," which I hadn't encountered yet. Developer Michal Strehovsky will gladly send you an unlock code, as long as you send him a picture postcard. Nice!
[ via gHacks ]