Mine is not so much memorable to me for baseball reasons, as for how we got the tickets.
When my oldest son was 8, he collected baseball cards. He opened a pack of Topps and got a card that said, "you have won two tickets to a MLB game at the location of your choice." This was very exciting, and he sent it in for the Cubs, because that is my husband's team, and it was very hard to get tickets to see them. Several weeks later, he got a letter that said, "because of high demand for the team you selected, we will give you the tickets not this year, but next year." So of course we forgot all about it.
A year later, out of the blue arrived an envelope with 2 tickets for a Cubs game in August. We had to rearrange our summer vacation plans, and I immediately went online and miraculously found two more tickets, so that we could all go. Youngest was two, and he sat on my lap. It was a sold-out game against the Mets, and was Tom Glavine's 300th win, although that didn't mean much to me at the time - I was too busy with the 2-year-old. But it was a really fun evening.