On July 12, 1962, Hank Aaron capped off a Braves rally at County Stadium in Milwaukee with a walk off blast that led his club to an unbelievable comeback 8-6 win over the visiting St. Louis Cardinals. Hank's kid brother Tommie led the rally off with a one out pinch hit home run off of the Cardinals starter Larry Jackson who proceeded to give up a single before getting the hook. Lindy McDaniel came into relieve Jackson, and served up a single to Mack Jones, then walked Eddie Mathews. The table was set for one of the greatest sluggers of all time, and he cleaned it off with one swing of the bat that sent the ball sailing into the seats in left. It was the first time that brothers had hit home runs in the same inning since 1938 when Lloyd and Paul Waner of the Pittsburgh Pirates accomplished the feat.
Tommie Aaron's career in the major league ranks was not one that led to Cooperstown. He hit just 13 home runs that were scattered over seven big league seasons. The '62 season was his rookie campaign, and it proved to be his best from a power standpoint, as he hit eight of those thirteen during that season. Three of those eight came on the same day that big brother Hank connected on a big fly. The first time it happened was exactly one month to the day that the two siblings helped put together a rally to be remembered. The third came on August 14th of that season. With Tommie's 13 added to Hank's 755, the Aaron brothers hold the record for sibling home runs with 768 total.
This link is a great piece about brothers who have paired up on a baseball diamond throughout the history of baseball: http://research.sabr.org/journals/baseball-brothers
Check out the box score here: http://www.baseball-reference.com/boxes/MLN/MLN196207120.shtml