travisl found M.P. Coin Exchange (Traditional Cache)
The group I was with found the cache, and having read the cache page, we attempted to swap out a coin for the one that was in there.
Suddenly, a piece of the cache container popped off and went flying a good ten feet away. The cache didn't have a log, so I just made a mental note of what the container was, and headed back to the car, while the others attempted to reassemble it.