The Mets played the Phillies tonight in Citizens Bank Park in Philadelphia. I've been to this park, and I absolutely love it. It's termed a "bandbox," a term which most baseball fans understand, but might have no idea where the word comes from.
According to The Dickson Baseball Dictionary (c) 1989, the term was originally used to compare the size of a small ballpark to the bandstands, or band boxes, that were once commonly found in small towns, and in which local music groups would play.
bandbox / band box / bandbox field n A ballpark whose small dimensions make it easier to hit home runs. In the 1950's the label was often applied to Ebbets Field, while today it is most likely to attach itself to Fenway Park (which John Updike termed a "lyric little green bandbox") and Wrigley Field. The term is sometimes used to suggest that a batter's numbers are less impressive because of the dimensions of his home field. At the end of the 1988 season, Jose Canseco of teh Oakland A's said that the record posted by Mike Greenwell of the Boston Red Sox was diminished "because he plays in a bandbox."
The first published usage found is in a 1906 issue of Sporting Life.