It was way back in high school, when I was still a teenager. My boyfriend at the time made a puzzle of me and him, and it was awesome. He also arranged a scavenger hunt in his parent's house. When I got to the end, there was a large trunk filled with all of my favorite stuff (at the time, it was Skittles and Snapple). I'll never forget that.
I had a really nice Valentine's Day with my current boyfriend as well, last year. He came over around midnight (this was before we lived together) with a stuffed animal and a rose, thinking I'd be asleep. It was sweet. The next day, we had a really nice date at the movies and a restaurant we both like. It wasn't where we went that made it so nice; it was just being with him. I was so happy back then. The right person can make anything, even a trip to the grocery store, seem fun.