The internet, probably the greatest invention by Al Gore since global warming.
Outside of Google Earth and some GPS software which allows me to keep tabs on Shania Twain 24/7, the next best thing is Retrosheet.org which has the box score of every single baseball game played.
I couldn't remember much about about the first baseball game I ever went to outside of it being in the nosebleed section of Riverfront Stadium, we got there late, the Reds played the Pirates and beat on John Candelaria; or at least that's how I remember it.
The site let's you cross reference any box score you may want by player, team, umpire, date, etc. It's awesome.
My memory was pretty clear on the game. The Reds had to have won by a dozen runs. It turns out they only won 5-3.