Mr. Tweak-a-Thon.

This would be worth trying if you have one of those mysterious refrigerators at work where your food items frequently disappear.

Not exactly about cooking but food-related. Here in Spain, marzipan figures are a common Christmas treat. I mean these:
http://rgarciaandsons.com/wp-content/uploads/2012/10/Dona-Jimena-Figuritas-De-Mazapan-Marzipan-Figures-100g.jpg

When in their original state, they are sweet and soft but when kept for a year, they become hard as stone and impossible to tell apart from the fresh ones.

Figure yourself the rest...

When I used to go camping the common way to cook baked potatoes was to wrap them in aluminum foil and place them in the fire. If someone left their potatoes unattended we would sometimes replace them with rocks wrapped in aluminum. That way when they came to check if they were soft, a sign they were done baking, it would appear they were never done cooking.

I used to play a prank on people. Back in my gum-chewing days when I was a kid, I'd get some gum that came in foil wrappers (Big Red - don't know if they sell it anymore.) I'd take a piece out of the wrapper for myself, and then carefully re-fold the wrapper so that it looked like it still contained the gum. Then I'd give people the empty wrapper.

This is how Jack in the Box food is prepared.

Still more nutrition than a Twinkie. (Sorry...Too soon?)

I like to do a similar thing with razor blades and apples. I know! Hilarious!