Marlins Park plays differently with the roof open or closed:

With the roof open and the left-field panels closed during batting practice Tuesday, the Marlins took advantage of a “jet stream” in the stadium, repeatedly blasting the left-center field sculpture with well-carrying home run balls. When the roof was closed because of oncoming storms, the balls lost some of their zip.

We’ll see if they open and close the roof depending on which team is at bat. 🙂 (Actually, I believe there are very strict rules about opening and closing retractable domes.)