Douglas Dinsmoor at his Open Stance blog writes a piece about being a baseball detective. It seems a movie was filmed in Boston with a Red Sox game figuring into the equation. Using all sorts of clues from the movie, a Baseball-Reference.com reader was able to pinpoint which Red Sox game was being filmed, the inning, who was on base, etc. Douglas applied that to his foul ball and home run baseball collection. He pieces info together from the ball, his memory, ticket stubs and so forth to figure out which game he snagged a particular ball.
I've done the same thing, and it's really fun. I just remembered as I started typing this that I used to tag each ball - including batting practice balls - with a piece of masking tape that had all the info on it. Date, inning, who hit it, all of that. I kept them all in a big box. Over the years, the masking tape lost its stickiness, and many of the tape pieces fell off. So I've had to do some pretty detailed detective work to get the proper labels back to their rightful owners. Some of the clues are whether it's an AL ball, NL ball or the newer MLB balls. Who's signature appears on the ball and when was he the league president? Was umpire's mud rubbed into the ball? This may help distinguish the ball as a game ball or batting practice ball.
Dinsmoor's is the first baseball blog I ever read and his was an inspiration, both in layout and content. We have quite a lot in common, baseball wise, and some things not.