I've created a puzzle of my own, of a similar type to those I've had so much fun solving recently. If you visit here you will find one image and one sound file. Hidden away within each is half of a gift code for my favorite GOG of all time, so you'll have to solve both of them to get it. Be warned: Although they aren't impossible, (or even particulaly tough, compared to some I've seen,) they certainly aren't trivial. A decent level of IT knowledge and a good chunk of free time is required for both.
If there's enough interest I may make a series of it, with better prizes. Until then, for those of you who are into this sort of thing, enjoy! :)