One of my hides that comes to mind is one near a scenic overlook, around some boulders. You have to reach up over your head for the cache, and tucked behind the cache with juuuuust enough fishing line for you to get the cache halfway down is a nice hairy spider that comes down from the hole to, um, "greet" you. I've got so many emails offline about that one to keep me laughing!
From this morning, "At that moment, I just couldn't understand why that &$%# thing kept coming at me!"