As in Andre and Mike Agassi. Luke and Bill Walton. Stewie and Peter Griffin.
Good, then bring on new Dallas Cowboys defensive coordinator Rob Ryan. And may his father, Buddy, suffer from eternal gas.
Rob is the twin brother of New York Jets' head coach Rex Ryan. He's the animated dude with the long, silver hair you've seen prowling the sidelines for the New England Patriots (where he won two Super Bowl rings), Oakland Raiders and Cleveland Browns (where his aggressive 3-4 defense jumped from 31st to 22nd this season).
He's fun. He's flamboyant. He's football.
He's -- son of a bitch -- the spawn of one of the most hated NFL personalities of a Dallas Cowboys' generation.
No doubting Buddy Ryan's defensive genius. The guy helped gameplan the New York Jets to their Super Bowl III upset of the mighty Baltimore Colts and was the architect of one of the best defenses in NFL history -- the 1985 Chicago Bears.
As head coach of the Philadelphia Eagles, he also became the Cowboys' No. 1 nemesis. In 1987 he had quarterback Randall Cunningham fake a kneel-down, only to rise and throw a touchdown pass in the final seconds of a blowout win over Tom Landry's team in Philly. And in 1989 he drew the ire of Cowboys head coach Jimmy Johnson for offering to pay any Eagles player $200 for knocking Dallas kicker Luis Zendejas out of the game.
Said a furious Johnson after that Bounty Bowl, "I have absolutely no respect for the way they played the game, I would have said something to Buddy, but he wouldn't stand on the field long enough. He put his big, fat rear end into the dressing room."
When he was head coach, Wade Phillips would often bring his dad, Bum, to practices. Here's hoping Rob Ryan's papa doesn't get the same invitation.