Jim and John Harbaugh will make Super Bowl history on Sunday when they coach against each other, and with a camera focused squarely on their parents, siblings and other family members, we'll get a sense of their gamut of emotions.
The brothers from Toledo, Ohio lead their San Francisco 49ers (Jim) and Baltimore Ravens (John) to the field in New Orleans and, amid all the media hype, it's easy to get blasé about what really is a remarkable feat. In nearly a half-century of Super Bowl play, brothers haven't even been on opposing sides as players.
Here's a look at some other sibling competitions, with an emphasis on championship meetings.
There have been several brother-brother and even a few brother-sister combos in racing, but none more accomplished than Germany's Schumachers.
Michael and Ralf finished 1-2 on five different occasions in about a decade of racing on the Formula One circuit, but it almost didn't get to that point when then-rookie Ralf bumped Giancarlo Fisichella at the 1997 Luxembourg Grand Prix, his own car just barely clearing brother Michael's Ferrari.
The first time Ralf got the better of the more accomplished Michael, who is older by seven years, was at Montreal in 2001.
In the very next race, the European Grand Prix in Nurburgring, Michael crossed first. The eventual seven-time drivers' champion had no compunction as his team successfully lobbied for a 10-second pit stop penalty for Ralf, which helped change the outcome of the race,
Brothers have not met in the World Series in nearly 50 years, since Clete Boyer and the New York Yankees met Ken Boyer and the St. Louis Cardinals. The family had nearly enough to field their own teams, as Clete and Ken were among a brood of 13 children, and all six of the boys played pro ball.
In the 2007 New York Times obituary for Clete, younger than Ken by six years, it was said that their mother opined ahead of the 1964 World Series that she was pulling for "the fellow on third base."
Both brothers played that position.
Each Boyer homered in the series, with Ken connecting on a Grand Slam as the Cardinals won in seven games.
Doc and Jimmy Johnston (Cleveland vs. Brooklyn, 1920), and Bob and Irish Meusel (Yankees vs. New York Giants, 1921, 1922, 1923) were the only other brother World Series acts.
All of the occurrences involved fielders. There has never been an instance of a pitcher trying to get his brother out in a World Series game.
The heavyweight title has been splintered more often than not over the past 35 years, so it's unreasonable to blame current beltholders Wladimir and Vitali Klitschko for not wanting to meet. Yet that hasn't stopped some boxing observers from doing just that.
Wladimir recounted one spirited session between the brothers when they were much younger.
"As you can imagine, it was bloody," he told The Daily Mail last year. "We have incredible love for each other, but there is also incredible competition and hate."
There's never been a championship-calibre meeting between brothers, but there's been about four or five fights involving siblings in the sport's history.
Marty Jakubowski, who once fought the legend Julio Cesar Chavez, stopped brother Eric Jakubowski in five rounds in a 1993 bout.
One year earlier, Australian Steve Thorpe won a three-round decision over twin Kevin. Thankfully, they wore different trunks to prevent the judges from going batty.
"If I'd had the chance to knock him out, I would have," said the winner.
Carol Niedermayer said in the spring of 2003 that she was pulling for son Rob and his Anaheim Ducks over his younger brother Scott and the New Jersey Devils. Scott, her reasoning went, had already won the Cup on two previous occasions.
It didn't pan out that way, with the two brothers embracing in the handshake line after the Ducks lost in seven tough games. But, a happy ending: As teammates they would be part of Anaheim's championship squad four years later.
The last time brothers had squared off for the Cup was in 1946, involving centre Terry Reardon of Boston and defenceman Ken of Montreal.
Terry scored four of Boston's 13 goals, but the Canadiens won in five games. The brothers were undoubtedly just happy to be playing in the NHL again, as they'd both served in World War II.
Decades earlier, two sets of brothers played for the right to reach the 1923 Stanley Cup final: Cy Denneny and George Boucher's Ottawa Senators ultimately defeated Corb Denneny and Frank Boucher's Montreal Maroons.
Jerome and Kevin-Prince Boateng are half-brothers, sharing the same father. Both played for German youth sides internationally, but Kevin-Prince would join the senior team for Ghana, the nationality of his mother.
It helped set up the first ever World Cup matchup between brothers, on June 23, 2010.
Things were spiced up by the fact that Kevin-Prince had seriously injured German Michael Ballack with a tackle earlier in the year. Jerome said his brother should have incurred a red card on the play, which didn't go over well.
All of that buildup and ... the Boatengs didn't really cross paths on the pitch in Germany's 1-0 victory over Ghana.
Venus and Serena Williams, separated by 15 months, have taken championship showdowns between siblings to a level that may not ever be matched in any sport.
The sisters have met in eight Grand Slam finals, with the younger Serena holding a 6-2 advantage. Unfortunately, when one thinks about the classic matches involving the pair, their head-to-head matches don't rank highly. Just two of the eight Slam matches went three sets.
The first such meeting, at the 2001 U.S. Open, lasted just 69 minutes.
"If I was the younger sister, maybe I'd feel more joyful," said the winner, Venus. "I don't exactly feel like I've won. If I was playing a different opponent, I'd probably be a lot more joyful."
By the time of the 2009 Wimbledon final won by Serena — which looks more and more like their last meeting in a Slam final — it had seemingly become old hat.
"I didn't think about Venus at all. I just saw her as an opponent," said Serena.
From Venus: "There's no 'easy' to losing, especially when you're this close to the crown."
Minutes after the trophy ceremony, the sisters were united again, on their way to winning one of their 13 Grand Slam doubles titles.