This story pales in comparison to most of what's been posted, but I'll tell it anyway, because it's the only story I have where I legitimately might have been in danger.
Back in high school (probably junior year, I think), I was in a long distance relationship with a girl from several states away. She would visit a few times a year and when she did, we obviously spent as much time together as possible. One night, we were kind of making up from a fight we'd just had and we drove up in my dad's truck to basically the Lover's Lane of the area - a dirt cul-de-sac at the end of a road on the mountainside. From this little lot, you could look out over the town at night and it was pretty cool, which is why it was kind of a popular place to go.
So we're parked in the truck just off the road, looking out over the town and cuddling while we talk out our issue. Like many trucks, it had a small hatch window on the back of the cab facing the bed of truck. We opened this to let some fresh air in. At some point during our talk, another vehicle pulled up along the cul-de-sac. Since I didn't make it clear before, the cul-de-sac didn't really have a curb all the way around it because it was partially dirt (I think there was construction in the area or something), so you could pull off the actual road and out onto the flat area overlooking the town. We had pulled off the road like that, but the other vehicle stayed in the area with the curb, so we'd have to go right past them to get back onto the road.
Anyway, this vehicle pulls up and a bunch of guys a little older than us get out and start messing around. Seemed like they probably were doing some drinking but maybe not. The thing is, they had left their headlights on and their car was facing into the back of the truck, so their lights were shining right on us and it was annoying. But we ignore them for a while, figuring they're probably just being idiots and will eventually leave.
Then, we get curious what they're talking about (because we can hear them talking loudly through the open back window), and we start listening in and picking up pieces of their conversation. It gradually became clear that we were the center of their attention and they seemed to be working themselves up to doing "something." I don't remember exactly what they were saying, except for something that one of them said that sticks very clearly in my memory: "I swear to god, I'll do it." At this point, I am becoming nervous, and put the keys in the ignition, telling my girlfriend that I wasn't interested in finding out what exactly was going on.
So now, we're both watching nervously out the back window as we listen to them egging each other on to this mysterious dare, when a few of them start walking toward the truck. They're maybe 15 yards away, and I don't want to make an idiot of myself in front of my girlfriend by immediately flipping shit, but I do turn on the truck and put it in reverse, but not moving yet. When they saw the brake lights, they started walking quicker, and that's when the NOPE button officially got pushed in my mind and I turned the truck around and started driving back to the road. But like I said, their car was between where we were and the road, so driving back to the road takes us right past them. As we're passing their group, a couple of them run at the truck and one of them jumps onto the back bumper, grabbing the tailgate. Now, whatever traces of doubt had been there about whether or not we were the target of something (innocent or not) was gone, so I floored it and the guy fell off. I don't know if he was hurt; I don't care. It looked like they were starting to get into their car as well, so I booked it out of the area and we didn't see them again, nor did we ever return to that place.
I still have no idea what would have happened if we hadn't gotten out of there, and that, to me, is the scary part. I'd like to think that they were just trying to scare us and wouldn't have actually done anything, but at the same time, I've heard stories of people at places like that getting raped/killed/whatever else. It's entirely possible that we both came very close to something horrible that night, and the experience scares me to this day.
TL;DR: girlfriend and I are sitting in my truck at Lover's Lane when car full of sketchy guys pulls up behind us and shines headlights in our back window. Sketchy group then begins to talk about doing something (never found out what), and it's clear we are going to be the subjects of this activity. They start walking toward the truck and I book it out of there. A few run at the truck as we're leaving and one manages to jump on and try to climb into the back before I floor it and he falls off.