My first concert........
Summer of '77, I was 15 and washing dishes at a restaurant I could walk to from my house (I owned a car, but wasn't able to get a license yet). It was cool, because I could basically hang out all night after we closed. We'd sneak some beer out and sit on one of the piers, listening to the radio and drinking. As with most restaurants, lots of young people worked there. Two coworkers were black guys in their late teens or early 20s.
Anyway, we were closed on Mondays and the business decided to spring for a trip to Kings Dominion near Richmond, VA. Everyone could bring a guest. I didn't take anyone but one of the guys mentioned above brought a girl - which shocked all of us, since it everyone knew he was gay (it wasn't accepted then, really, but he was so well-liked it was a DADT kind of thing). Well, the girl latched onto me when we got to the park. I didn't know what the hell was happening, as she was 18 and I wasn't used to girls being that aggressively interested in me. I still don't understand it. I was a skinny, pasty white kid and she was - in my eyes - a full grown woman who was as dark as I was white. At the end of the day, she gave me her phone number and laid a liplock on me that I hadn't experienced before (or since, for that matter). "Call me".
(don't worry - this isn't a Penthouse Forum post)
So, I would call her from a pay phone just about every day and we'd talk for hours each time. During one call, she asked if I wanted to go to a concert with her, her sister, and sister's boyfriend (the gay chef's brother, as it turned out). I said sure, not knowing how I was gonna pull that off, since I knew I couldn't ask my parents for permission (it was Maryland, but still below the Mason Dixon Line and some in my family weren't the most enlightened folks).  Then it hit me that all I had to do was tell my folks I was working the night of the concert. They were used to me not getting home until 3 in the morning. No problem, right?
They picked me up at the restaurant. I hid behind the dumpsters until they showed up because it was a small town and everyone knew everyone and everyone talked about everyone (and my father was a regular at the bar there).
The show was at the old Cap Centre in Landover, MD (where the Bullets & Capitals used to play). KC & The Sunshine Band was the headliner. The Trammps and The Jimmy Castor Bunch were also on the bill, along with two or three others. It was a general admission show (no seats on the floor) - one of the periodic "Summer Fun" concerts they'd put on there.
I remember the opening band was horrible. I don't recall their name, but it looked like they were dressed in tin foil to look like " funking robots" (according to the singer, who said that a million times in their 4 or 5 songs). There was another band in there I have no recollection of.
Then Jimmy Castor came out. His act was like a cross between Alice Cooper and Screaming Jay Hawkins. He actually probably put on the best "show" that night, as he and his band were full of seasoned pros and had their act down. But I got distracted during his set, because I got robbed. The girls had gone to the ladies room and I don't know where the hell Jeffrey went, but three dudes - all bigger and scarier than me - came up and took what little money I had, along with my cigarettes. Right after that. some great big guy who looked like Aaron Neville with a bad hangover came up to me said "you can't let people take you like that, man". I'm like "why didn't you help me then?". He just shook his head and left  
 
 
Well, my date didn't let me out of her sight after she learned what happened. Kept asking me "you ok? you ok?". I reckon I was still in a little bit of shock, but I was more pissed about the cigarettes than the money. 
The Trammps were next and they got off. I can't recall if Saturday Night Fever had hit big yet at that point, but I knew "Disco Inferno" and "Where The Happy People Go" from the radio so they weren't unknown to me. They were fantastic and did this really cool thing where they would appear to change costumes by changing the lighting. I'm sure it was cheesy to a sophisticated eye, but I didn't have one of them.
KC was a bit of a disappointment. Maybe it was the sound system or something, but they didn't sound good. And he doesn't have the world's greatest voice anyway, so he couldn't sing through it.
Later on that night, I got laid for the first time and went home with a huge hickey on my neck (which mortified my mother).