Found this one near the Natural Bridge in Virginia. Carved out section of wood the size of the small Altoids, painted white like the fence and hangs on a screw on the fence (the hardware is above the Altoids). Totally blends in.
How To Make a Cryptex - this would make an awesome evil cache. You have to know the book, put it in a place somehow associated with the book and know the 5-letter word code. (I know what it is, but I admit I'm just not this clever or handy!)
Sneaky fake grass nano #geocache. I actually like the placement of this one; being sort of on a tree base, it makes it look a little out of place and therefore a better chance of the observant person finding it. Hidden in a field? Probably forget it till spring when all the real grass is yellow.