The coolest part sometimes, is the pure genius of the cacher. I searched circles around a tree once on the side of the road. my GPS was telling me that i was right on top of the cache, but i couldn't find it to save my life. Then my wife noticed an Electrical conduit box. You know, the skinny green ones with orange letter stickers on them. Yeah, it was one of those... Only with a wingnut on the front, and the numbers oddly enough matched the GPS coordinates. Sure enough, behind the wingnut panel was a geocache container!
I have also seen hollowed out logs, fake birdhouses on trees, the infamous hollow magnetic bolt, and even a pigeon decoy stuck in a tree, with a film canister cache built in. Once, in a tree, about 6 or 7 feet up there was a crotch with a small hole in the center of the crotch. There was a nail, with a piece of wire, and on the end... you guessed it, a cache of a piece of paper, and a pencil. Another classic was a metal box in a parking lot of a shopping center. The box had a combination lock on it, and the combination was on a big sticker right there on teh side of the box for everyone to see. Some caches are simply landmarks. Take a picture of you in front of Rainbow Records in L.A. to claim that cache on your list etc. etc. The sky is the limit.
Being a woodturner, I thought about taking a piece of wood, and hollowing it out, and "turning" it into a limb looking situation and putting it in a tree. Maybe offer a nice prize for the FTF (First to Find)
a little tip before you start. RESEARCH THE CACHE. A little "digging" (no pun intended) goes a long way. Make mental notes of the details because they will help you in that last ten feet. Check comments to see if you can judge if the cache is still there, and in decent shape. I have actually found caches without using a GPS at all. It is also considered good caching ettiquette to "Cache in, Trash out" Which means that you should take a garbage bag with you, and pick up any trash you might see along the way to the cache, and then again on your way back out of the cache.
Yeah.. caching is fun! Ironically, I think alot of the "tricks of the trade" could be crossover for detecting or caching. clipboard, hardhat, orange vest and electronic gadgets equal the impression of official business.