On Monday, I attended the first-ever game between the Brooklyn Nets and New York Knicks at Barclays Center. I won't get into the game itself -- our own Shaun Powell did a terrific job on that. I'd rather talk about the crowd.

It was, to my amazement and delight, one of those lovely sports rarities: a 50-50 crowd. I'm not sure there's any more fun sporting event to witness in person than a sold-out game in which the rabid fanbases of both teams are split almost exactly down the middle. I'm not talking about the Super Bowl or a college bowl game, when the stadium is mostly full of corporate sponsors, contest winners and "friends of the league." Those people don't care who wins, and the atmosphere there is basically that of a loud exhibition.

No, I mean a game when the place is packed with people who desperately want their team to win, a game in which there are two home teams. In which there is a massive roar every time anyone scores. In which there is a competition in the stands as well as on the field/court/diamond. A 50-50 crowd game.

There are two sorts of 50-50 crowd games, one a bit more exciting than the other. The first is like what we had at Barclays: a game in which the visiting teams' invading fans fill enough of the place that there's simply as many fans of the road team as there are of the home team. These are often less rivalry games and more a matter of one team in a major metropolitan area having a lot more fans than another team's. Common examples of this include Yankees fans invading the Mets' Citi Field, Cubs fans invading the White Sox' U.S. Cellular Field, the NHL's Rangers invading the Islanders' Nassau Coliseum, and Nebraska football, Kentucky basketball and Steelers fans invading anywhere. (For years, Arizona Cardinals fans dreaded Cowboys games for this very reason.)

This one is not quite as much fun, if just because the cheers of the home team feel almost defensive, a way to claim back their arena/stadium/diamond from the hostile takeover artists from across town. The best way to identify one of those is by flipping the script: Play the game at the other team's arena/stadium/diamond, and the road team could be anybody. (This is another reason USA soccer home games against Central American teams can be depressing.) When the Nets play at Madison Square Garden, they might as well be the Celtics or the 76ers; no one ever says, "Oh, the Mets fans are taking over Yankee Stadium!" It's a one-sided 50-50 game; it's because of one team having a huge advantage over the other rather than an inherent equality. That doesn't mean those games aren't enjoyable: Monday night was a blast. (And the Nets still have lots of time to build up more of a homecourt advantage over the Knicks.) It's just not the perfect case.

True 50-50 matchups are extremely rare. They require:

• Historically successful teams. Generally speaking, the opponents need to be at least somewhat competitive with each other throughout the years.
• Geographic closeness. Goes without saying.
• Passionate fanbases. Ditto.

• Neutral location. Having a game on a team's home court/stadium/diamond is always going to tilt the scale one way or the other. You need a place where everyone on both sides must travel, preferably a place equidistant.

• Regularity. This is the key. It can't be a one-time deal: This has to be a destination game, every year, when rivals who otherwise don't cross paths all come together to gauge where they are.

You won't find many of these, and they thus must be cherished. The most famous of these is the Red River Rivalry, in which Texas and Oklahoma dissect the Cotton Bowl almost exactly down the middle. (Here's a great photo showing just how precise the dissection is). Texas and Oklahoma are teams with vast fanbases that often overlap each other; in some cases, it's quite literally brother against brother. You can make an argument that it's the pinnacle of the sports fan experience: people crammed into one area, shoulder to shoulder, screaming their lungs out with no cynicism and no irony. It shows how sports unite and divide us, and why that's so great.

I've never been to the Red River Rivalry, but I'm fortunate enough to cheer for a team that has its own 50-50 game. My Illinois Fighting Illini basketball team plays Missouri in St. Louis -- a city that's roughly in the middle; having it in Chicago or Kansas City would ruin the whole thing -- every year in the Braggin' Rights game, just a few days before Christmas. For years, I've been planning my holiday trips home just to make it in time for that game. It's two hours of people in orange screaming at people in black, and vice versa. After the game is over, each team goes its separate way, see ya again next year. It's the primary reason I was terrified that Missouri was going to join the Big Ten: It would have ruined that too.

Other great ones included the Big Five games in Philadelphia, Georgia-Florida at the Game That's No Longer Called The World's Largest Cocktail Party Even Though Everyone's Always Blasted At It Anyway Game in Jacksonville, Xavier-Cincinnati in college basketball and the Army-Navy game, though that's a little different.

You'll notice that almost all those games are collegiate, where tradition and rivalries make more of a difference. Which brings us back, again, to realignment of college football conferences and the now-total control that money has over college athletics. Indiana-Kentucky could be one of those, but no one wants to give up a home game. Kansas-Missouri, now that they're in different conferences, would be perfect, but no one's doing that one, either. These games work because fans have longer memories than players, coaches and administrators do; they work because we're the ones who make these games matter. (And also: These games aren't as much fun on television.)

With so few true 50-50 games remaining, I'll take the artificial ones, like the Nets-Knicks at Barclays, while I can get them. But I just wish there could be more. Everyone should get to go to these. They remind you why this is just so much fun.

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I'll be at the Braggin' Rights game again this year, and I cannot wait. It should still have Busch beer as a sponsor, though. (Also: There's not much better than a collegitate sporting event that actually sells alcohol.) Thoughts, concerns, grousing, future column ideas? Remember, this column is meant as a valve, a release, for when you're yelling at your television during games, or, after reading a particular column, you're pounding your fists into your computer. Obviously, I'll need your help to do that. Anything you want me to write about, let me know, through email or Twitter. I am at your beck and call.