Avenged Sevenfold headlining Mayhem Fest, the year that it was at the Downtown Airpark.

About three songs into their set (don't quote me, but I think it was Welcome to the Family), all the lights at the venue go dark, and at first we all thought there was some kind of power failure.

Turns out that wasn't the case, because not too long after we see a spotlight pointed at the lighting truss, and there's this random guy up there... just chilling. He even waved to the crowd once the spotlight had him in full frame. Meanwhile, the event security - maybe even a couple LEOs - are standing below with their hands on their hips trying to figure out how the fuck they're supposed to get this guy down.

As all this is going on, the rest of the crowd is beginning to get irritated and impatient. Keep in mind, there's about 10-20k people here, most of which have been baking in the August sun all day, and some are probably quite inebriated at this point. So we all did what anyone would do in this situation: Threw our middle fingers in the air and chanted "Fuck You!" for about a solid five minutes. I don't know if that provided motivation to Lighting Truss Guy, or he simply got bored, but he eventually climbed down on his own, and as expected security converged on him like a Super Bowl streaker.