Irving Chernev, who wrote "Wonders and Curiosities of Chess," would have loved this. The following two games were both played at the U.S. Open, five years apart. The White players were brothers from Chicago named Albert and Angelo Sandrin, who both became Life Masters. In both games, White played exf7+, to which Black responded with ...Kh8. A few moves later, White captured Black's rook on f8 for free and with check, checked again with the capturing piece in order to vacate the f8 square, and then underpromoted his f-pawn to knight, checkmating Black. Commenter "Phony Benoni" (David Moody) at chessgames.com calls the games "definitely a case of sibling rivalry."
Albert's game is from the 1949 U.S. Open, which he won ahead of such luminaries as Larry Evans, Arthur Bisguier, and Anthony Santasiere.