[Eric72]

I was watching a YouTube video today, This Week In Baseball from August 9, 1977. One of the plays was an inside-the-park Grand Slam. Uncommon, yes; however, that has probably happened at least one other time. It got me thinking, though. What are some things that have only ever happened once in MLB history?

Two that immediately came to my mind were Johnny Vander Meer's back-to-back no-hitters and Fernando Tatis' two Grand Slams in the same inning.

Another (sorry, Yankees fans) was the Boston Red Sox winning a playoff series after they had fallen behind 3-0.

Let's see what we can come up with here.