Pick a side: Wildcats or Cardinals. Rupp's Runts or the Doctors of Dunk. Dan Issel or Wes Unseld. John Calipari or Rick Pitino.
"If the excitement and frenzy and turbulence that's been stirred up in Kentucky this week could be harnessed, we could solve our energy crisis," Kentucky Sen. Mitch McConnell said on the Senate floor. "Basketball fans from Kentucky have been waiting their whole lives for this game."
This is the grudge match to end them all.
It's the fifth time the schools will meet in the NCAA tournament the two sides have split the four previous meetings and it pits Louisville coach Pitino against one-time friend and now frosty foe Calipari. Not to mention Kentucky freshmen phenoms Anthony Davis and Michael Kidd-Gilchrist, who have been steady in taking the Wildcats to the top, vs. a ragtag flock of Cardinals who've won eight straight with a rotating cast of mostly unknowns such as Peyton Siva and Gorgui Dieng.
"It's not about (Pitino) or I; it's about these players," said Calipari, who's in his second consecutive Final Four still searching for the national title that's eluded him. "Hopefully we both have our teams ready to play, and I think we will, and we'll go at it."
The Cardinals (30-9) lost this year's matchup vs. the Wildcats (36-2) 69-62 on Dec. 31. Even though there is much more on the line Saturday, it will be difficult for the game to be much more intense.
"There's going to be so much pressure on the players," former Louisville forward Earl Clark said. "It's going to go down in history. Kentucky is the No. 1 team, and Louisville is like the Cinderella of the tournament."
Kentucky blue dominates most of the state of more than 4.3 million basketball-crazed fans, surrounding the outnumbered Cardinals fans who have fortified a stronghold in the state's largest city.
The fan bases are about as different as they can be, and Pitino is one of the few who knows what it's like on both sides of the aisle.
He coached Kentucky for eight years, bringing the 'Cats back to the pinnacle of greatness with an NCAA title in '96. He's been at Louisville for the last 11 years and is heading to his second Final Four with the Cardinals.
"It's two different entities, really, it's two rabid fan bases," Pitino said.
That was oh so clear this week when two senior citizens duked it out at a Georgetown dialysis clinic.
A 68-year-old Kentucky fan and 71-year-old Louisville fan were arguing Monday about who will win Saturday's game when the discussion quickly got out of hand. Georgetown police Lt. Robert Swanigan says the Kentucky fan flipped off the Louisville fan, prompting the Cardinals fan to punch him in the face. Though police were called, Swanigan said the Kentucky fan declined to file charges.
The fight likely wouldn't surprise Kentucky coach Calipari, who lovingly compares Wildcats fans to piranhas yes, the flesh-eating fish.
"If you're going to attack Kentucky, just be right," Calipari said of a fan base that feeds off every little bit of information about his school and dissects every game tape three times. "I'm just telling you: piranha wahp-wahp-wahp-wahp-wahp-wahp. They'll come and eat your yard, your house. These people are nuts."
And Cardinals' fans enjoy poking fun at them.
On Twitter and message boards, they joke how Kentucky fans turn Cats into two words Ca-yuts. One of Big Blue Nation's favorite retorts? Loserville.
Pitino jokes many marriages in the state fail because they have a Louisville woman marrying a Kentucky man.
Nick Fenton and his wife, Christi, are working through their differences in Louisville. Fenton said they fly a "House Divided" flag in their front yard with the two schools' logos displayed.
"Her family is all Cards fans, so they brainwashed her," said Fenton, who usually reserves the rhetoric for one week a year. "This Final Four game, though, it's going to be pretty wild."
It took the governor to first get the two schools together on an annual basis.
Kentucky never scheduled in-state schools under coach Adolph Rupp, and former assistant Joe B. Hall dutifully followed suit when he took over as coach. Gov. John Y. Brown stepped in following their matchup in the 1983 NCAA Mideast Regional finals known around the state as The Dream Game. Louisville beat Kentucky in overtime in Knoxville, Tenn., in the teams' first meeting since 1959.
"It created a lot of animosity and strong feelings toward each other, but at the same time I felt like the taxpayers were entitled to see the competition between two of the nation's premier programs," the former governor said. "If you ask either school what the No. 1 game on the schedule both in basketball and football, they'll say it's the rival school.
"They have to live in shame, whichever one loses."
Kentucky vs. Louisville is a matchup of cultural divide that's steeped in history with nine combined titles between the two schools, the same number as the more publicized North Carolina-Duke rivalry.
Former Kentucky guard and No. 1 NBA pick John Wall remembers the wild scene before the only rivalry game he played in 2010 more than the contest itself.
"I didn't think it was that big until we played them. There was about to be a big brawl at the beginning of the game. Technicals both ways," said Wall, star guard for the Washington Wizards. "All you hear from the fans is, 'Don't lose to the Cardinals. Whatever happens, Big Blue Nation better not lose to Louisville.' "
For the most part, Kentucky fans have gotten their wish the Wildcats are 18-11 since the annual game started in 1983-84 to go along with seven national titles and 15 Final Four appearances. Louisville has two titles and is making its ninth appearance in the national semifinals.
The histories of the programs highlight their differences in style and their efforts to keep up with each other.
Louisville's decision to build the $238 million KFC Yum! Center downtown hastened Lexington's plans for a $150 million renovation of 36-year-old Rupp Arena. And both schools built multimillion dollar practice facilities in the past few years
Louisville signed its first black players in 1962 with a class that included Wade Houston, Eddie Whitehead and Sam Smith with little fanfare and later inked greats like Unseld and Darrell Griffith.
Kentucky was famously slower to integrate.
Rupp's all-white team lost to Texas Western, which started five black players, in the 1966 NCAA finals popularized by the movie "Glory Road" and didn't break the color barrier until 1969 when Rupp signed Tom Payne of Louisville who spent a year in Lexington before entering the NBA draft.
When the dunk was reinstated in the college game for the 1976-77 season, Louisville and coach Denny Crum embraced attacking the rim, beginning with Griffith, who earned the moniker "Dr. Dunkenstein."
Crum won titles in 1980 and '86. His high-flying players at Freedom Hall were known as the Doctors of Dunk, who helped popularize the high five and helped usher in a new age of college basketball, including a win in The Dream Game in 1983.
Kentucky's style bordered on a business-like approach under Rupp assistant Joe B. Hall. Hall's '78 squad was so thoroughly expected to win the national title that when they did, it's remembered as "The Season Without Celebration." Hall coached through 1985 before Eddie Sutton's unsuccessful run ended in NCAA violations.
It was Pitino who helped usher Kentucky back to the title path with three Final Four appearances and a championship in 1996.
That group, known as The Untouchables, featured nine NBA players and six first-round picks. Kentucky heads to New Orleans with a team loaded with talent whereas Louisville was a big surprise to get to the Final Four once again. It makes Saturday's game another historic showdown.
Former Kentucky forward Josh Harrellson summed it up: "I think everybody in the world is going to be watching."
AP Sports Writers Howard Fendrich, Brian Mahoney and AP freelance writer Ian Harrison contributed.
P Saturday, Ch. 2 • Kentucky (36-2) vs. Louisville (30-9), 4:09 p.m. • Ohio State (31-7) vs. Kansas (31-6), 6:49 p.m.