I would imagine that LARPing is not new to you, but just in case...
Here are some great videos I found!
This first video is about 4 1/2 minutes long and is a montage of some great footage of people LARPing. It is appropriately titled: "LARP Sadness." Amen.
Next up is a 5 1/2 minute film of a battle against a... DRAGON! My favorite parts are the random car that drives by in the background (I can't even imagine what would go through my mind if I were driving along, only to look over and see people dressed as wizards and dwarfs, running around a big dragon), the dude that gets taken out by the dragon's arm (and it looks like he really gets taken out by it), and the water or "acid?" that gets shot out of the dragon's mouth. Such realism. Plus, it is great how little is happening in it (everyone is just running around, but no one is fighting). It is called the "Wayfinder Dragon Battle" and is some sort of Finale? I don't get that.
Last up, an old favorite of mine. The classic "Magic Missile" video. If you do nothing else, make sure to watch this 30 second video with sound. You will not be disappointed.