Osso wants to hear more about what I mentioned as my all-time best date on another thread.
In 1977, I was 17 and a senior in high school and the Art Club raised $$ all year to go to Europe on spring break. We had 5 days each in London, Madrid, and Paris.
When we got to Paris, I had to go for an obligatory dinner at the home of my mom's college roommate. It was interesting to go to a private home, but I wasn't particularly looking forward to the evening. (I'm sure the other kids were doing something that seemed much more interesting.) As it turned out, the lady had two sons. They were 21 and 18 years old, and after dinner they planned to take me out on the town!
We went to see a movie. At one point, one of the guys was parking the car and the other went to meet him in the lobby. So there I was in a Parisian movie theatre trying to save two seats. I knew some French, but that was a bit of a challenge! The movie was American with French subtitles which causes some weird timing on the laughs.
At some point, the brothers realized that I speak some French, and so they switched to German when they wanted to talk over my head.

About that time I realized that they were definitely competing for me. Not a situation that I was used to. We talked and talked. Their parents are American but they'd almost never been here. They asked a million questions.
We went to a club and danced. (Disco was in.) I honestly don't recall if I had anything alcoholic to drink - I don't think I needed it at that point. We went to a cafe and they made me drink coffee. I never have liked it, and I'm sure that was my first cup.
So, okay, I picked the younger brother. Someday, Osso, when we meet in person, I'll fill you in on the really juicy stuff!
Tell us about your all time best travel experience!