I was either 16 or 17, and was staying over at a friend's house that was 50 miles from nowhere in upstate New York. He went by the name 'Raven' and lived with him mom on a skinny dirt road with only a few houses on it.
We decided to go for a walk to take a break from video games, and to smoke a few cigarettes where his mom wouldn't give us any shit, and while we're walking I start noticing some old stone walls up in the woods a bit, and a path that seems recently used. Intrigued, we followed the path up into the woods, hoping that we'd come across some pot plants or something good like that. Instead, after following the path along the stone wall for a bit, the woods opened up into a clearing that was obviously an old ass graveyard. There were maybe 20-30 headstones that were in various stages of decay, and an old wooden shack, all surrounded by a crumbling stone wall. There was a wooden entry arch at one point it seemed, but it had rotted away into nothingness quite some time ago.
So we start poking around a bit. My buddy walks off to the far end to check out one of the larger headstones, maybe to see if we could find one with a readable name, or something we could get a stone rubbing from. I walked over towards the shack to see what state of decay it was in. At this point I noticed that the shack had a lock on the front, and seemed pretty sturdy. I walked around to the back side, where there was a window. It only took a couple of seconds for me to realize that I was staring at a workbench that held a massive pile of human bones, complete with skulls, etc. All of them seemed bleach-clean, like something out of the movies. I turned to where my buddy had headed off to to see him running towards me. All he said was "dude, there's an open fucking grave over there." I pointed into the window at the bones and his eyes went wide.
Thoroughly creeped out at this point, we just took off back the way we came. When I asked about the open grave, he said that it looked like there was an old rotten casket down in the hole. So my best guess is that someone was excavating this old ass graveyard. For what purpose I'll never know, nor do I want to.