Did the windows startup theme one to a colleague once to teach him to lock his laptop when he left it (company security policy and grounds for one hell of a bollocking if you didn't).
Poor bugger had no idea until he was about to do a presentation to senior management and switches on his laptop to find Alvin and the Chipmunks singing Bad Day.
![whistle:](https://www.virtual-pub.com/SMF/Smileys/default/whistling.gif)