L. Gurriel and Y. Gurriel hit 2 hrs each today (9/21). I wonder if two brothers have ever done that before. I'm not even sure how to research that.

According to Elias, they are the first set of brothers to have done it. There have a few pairs who have homered in the same game or same day, but not multi-homers like the Cuban brothers. Some of those were the Alou, DiMaggio, Nettles, Conigliaro, Ripken and many others.