1.) Slayer and Machine Head at Download 2007. 60,000 people slamming into each other in blazing sunshine. Magical. My ribs were sore the next day, however I sustained only minor injuries considering my size(I'm a small guy). I saw a lot more people with slings/crutches after they played...
2.) Cancer Bats at an incredibly small venue. A few bruises after but a really good night. Memorable as I took a friend of mine with me, his first gig experience (bless!) and he was totally exhausted afterwards! "How the hell can you still move?!"
EDIT: That was it, I knew there was more to it, just coiuldn't remember. Turns out my friend face-planted the floor within about 5 minutes, a couple of people helped him up and he carried on for the rest of the gig, however he told me afterwards (he's quite a muscular guy) "You're fucking fierce considering your size!". Turns out I inadvertently sent him flying
3.)Was at a Gallows gig about a month ago, maybe a little more. Sheer chaos. I thought nothing was more intense than 60,000 Slayer fans. Turns out there is and it's 1,500 Gallows fans in a very small venue!
They asked everyone to form the biggest circle pit they could, refusing to play until nearly the entire floor was taken up. They struck the first chord for 'The Great Forgiver' and rather than a straight ahead circle pit we all charged wall-of-death-style, then after all the chaos turned it became a circle pit. Pretty funny because in one of the earlier pits I got totally wiped out by someone twice my size, went flying. Scrambling to my feet so I wouldn't get knocked down again another guy twice my size comes along and just grabs me by the arm and pulls me up "there you go mate". As it happens I ended up doing the same for about 3 other people. It's nice to see that people look out for each other from place to place.