For the little brother, it might be marbles, ping-pong or checkers. For the Nuggets, it's challenging the Lakers' supremacy in the NBA's Western Conference.
The little brother sometimes wins, but the big brother usually takes charge when it counts. Then again, if the little guy practices hard enough, sometimes even that can change.
So far this season, the Nuggets are 2-0 against the Lakers, with Game 3 Sunday at the Staples Center. You'd think Denver, which has won the games by an average margin of 19.5 points, really has gotten the attention of the Lakers. But that's not completely true.
Lakers center Andrew Bynum did call it a "statement'' game, one his team needs to win. But teammate and star guard Kobe Bryant quickly shot that down.
"He's young,'' Bryant said of Bynum. "I don't think it's a statement. I think it's an important game in terms of stepping up and responding to the challenge, their physicality. ... But 'statement game' is a little too strong.''
You get the feeling the Lakers aren't going to fully take the Nuggets seriously until they lose a playoff series to them. The Lakers crushed the Nuggets 4-0 in the first round two years and beat them 4-2 in the West finals last year, a series that could have gone the other way had the Nuggets not literally thrown away two games with faulty late inbound passes.
But what about the Nuggets crushing the defending champions 105-79 Nov. 13 in Denver?
"We played them in a game in which we got in at 4 o'clock in the morning,'' Lakers coach Phil Jackson said.
But what about the Nuggets winning 126-113 Feb. 5 in Los Angeles?
"They were 16-of-23 (actually 15-of-22) from the three-point line in that ballgame,'' Jackson said. "That's not going to happen every night. You know that as a coach.''
Jackson does say the Nuggets are "playing very good basketball.'' But, no, he still doesn't call them a rival.
Jackson said before the teams met for the first time this season it was not yet a rivalry. Two lopsided defeats haven't changed his mind.
"I think of a rivalry as a long-term (thing),'' Jackson said. "I think of the Celtics-Lakers, maybe the Spurs and the Lakers. ... If this ends up in a playoff situation, then it it will be three consecutive years against them in the playoffs, which does get there in rivalry fashion.''
Jackson doesn't deny his talk of it not being a rivalry yet has possibly contributed to the Nuggets feeling they don't get their due. All Jackson could do was chuckle when he heard of Denver star Carmelo Anthony saying last Sunday his team is "disrespected.''
"They feel very maligned, I know that,'' Jackson said. "If they're looking for the attention, they certainly have ours. ... They're just looking for motivation, and they certainly have a lot.''
But, if the Nuggets are looking for the Lakers to say it's a rivalry, they're not going to get that.
"No,'' said forward Pau Gasol. "It takes years to develop a rivalry. And, if we meet five straight times in the conference finals, that will be the mindset that we have something going on. But we only met them once. The year before, we met them in the first round of the playoffs. But that wasn't much of a series.''
Lakers guard Derek Fisher agrees.
"Not in our mind,'' Fisher said of it being a rivalry.
Of course, if the Nuggets can beat the Lakers a third straight time, that might get Bryant's attention even more.
"You never want a team to beat you three straight times,'' he said.
The Nuggets are gunning to do that. The Orange County Register made note recently about how Nuggets guard J.R. Smith wrote on his Twitter account, "Don't get me wrong, Kobe is great but not when he play me."
Not that the Lakers are paying much attention to this. When forward Lamar Odom was asked by a reporter about Smith writing on his Twitter page about the Nuggets (39-19) looking to overtake the Lakers (44-15) for the top spot in the West, Odom said, "We don't follow J.R. Smith's Twitter account.''
Even often-benchwarming forward Joey Graham is talking tough for the Nuggets.
The Lakers really, though, only will feel the blow if Denver can beat them in the playoffs. That might be the only way for the Nuggets to shed their little brother status.
Chris Tomasson can be reached at firstname.lastname@example.org or on Twitter @christomasson