It can be either a game that you watched or one that you participated in. Or both.
Reds related: My mom waking me up when I was 7 after the Reds recorded the final out in the 1990 WS to see the celebration on the field. I'm actually somewhat amazed that I remember that, but I do.
Participating: Playing catch with my dad in our back yard. Also: I was always a gap type of hitter when I played. But I hit ONE home run and I remember how perfect it felt and the PING that the bat made... such an awesome feeling. Too bad I only got to experience it once. On the other hand, at least I got to experience it one time.