I was lucky enough to get a jump seat flight on a Concorde when I was an air cadet (to the US and back). It was at very short notice, I had a phone call from my then CO on the Monday asking if I wanted to go on the Wednesday and even though it was the school term my parents (bless them) didn't have to think twice about saying yes. Luckily I had only recently got a new passport too.
What an experience and I was a saddened as many when the air transport industry took a backwards step on the retirement of the Speedbirds.