It's rivalry week across the Big 12. Old foes will be meeting in big games that will provide a year's worth of bragging rights to the winners and have huge ramifications on postseason plans.
The Bedlam Series, the Lone Star Showdown and the Border War (or the Border Showdown, as politically correct forces have mandated) will be contested this week. And although the Colorado-Nebraska series doesn't have a name or a trophy, don't tell the Buffaloes or Cornhuskers their annual meeting isn't meaningful.
Here's a closer look at the Big 12's four key rivalry games this week.
Texas A&M at Texas: The Lone Star Showdown
The battle between the two old rivals returns to its traditional Thanksgiving Day scheduling (ESPN, 8 p.m. ET) for the first time since 1993. It is the third-longest-running rivalry in the nation, and the most enduring rivalry for both schools.
The lineage of the Longhorns' famed mascot, Bevo, dates from this rivalry. Legend has it that the name of the mascot came from an incident of vandalism in 1917 involving Texas A&M students who kidnapped the longhorn and branded him with "13-0" -- the score of A&M's 1915 win over Texas.
Both schools count the matchup among their biggest games and host a rally before it. Texas promotes the Hex Rally for the Aggies, and Texas A&M students have conducted the Aggie Bonfire, although it is no longer a school-sanctioned event after the 1999 tragedy in which 12 students were killed.
Texas leads the series 73-36-5, although the Aggies have won back-to-back games after Texas claimed the previous six. It will have even more importance Thursday night for the Longhorns, who desperately need a big victory to improve their BCS standing. Texas A&M is playing for little more than pride after being eliminated from bowl consideration several weeks ago.
Kansas vs. Missouri: The Border War (Showdown)
History has made the Kansas-Missouri rivalry one of the most bitter in all of college football. The roots stem from the open violence that took place between anti-slavery and pro-slavery elements in the Kansas Territory and the frontier towns of western Missouri in the 1850s. It culminated in the infamous raid when William Quantrill's Confederate guerilla forces burned Lawrence, Kan., to the ground in 1863 and murdered nearly 200 people.
It has continued to be almost as bitter on the playing field. Politically correct forces at both schools have stressed rebranding it as the "Border Showdown" in the aftermath of Sept. 11, 2001. But there's a steady dose of antipathy on both sides.
Former Kansas coach Don Fambrough has been the most fervent, telling reporters over the years that the game should always be considered the Border War.
"They started the war," Fambrough has told numerous reporters, "and eventually we're going to end it!"
The Missouri-Kansas series is the second-most-played rivalry in college football history, beginning in 1891. The Tigers lead the series with a 54-53-9 advantage and have won two straight games after Kansas won nine of 13 games between 1993 and 2005.
This year's game won't get nearly as much attention, with the North Division already decided. But the Jayhawks would like nothing more than to deflate the Tigers' momentum for next week's Big 12 title game by beating them at Arrowhead Stadium in Kansas City, Mo., on Saturday.
Oklahoma at Oklahoma State: The Bedlam Series
The Bedlam Bell doesn't rank with the Old Oaken Bucket, Floyd of Rosedale or the Commander in Chief's Trophy. But for fans in Oklahoma, it's as big as any of those rivalries.
The series dates back to 1904, when Oklahoma beat the Cowboys 75-0 in a game at Guthrie, Okla. The Sooners produced a combined 240-0 margin in the first eight games before the Cowboys finally scored in 1914.
Saturday's matchup in Stillwater will be the first time both teams are ranked in the top 11 nationally since a 1984 matchup when Oklahoma was No. 2 and Oklahoma State was No. 3. And Saturday night's game likely will determine the Big 12 South's champion as the final game of the regular season.
The Sooners hold a decisive 79-16-7 edge in the series and have won five straight over the Cowboys. But Oklahoma State has played them closely in recent seasons, twice stunning them in big upsets that foiled the Sooners' national championship hopes in 2001 and '02. Oklahoma coach Bob Stoops has a 3-1 edge in previous games in Stillwater, although none of his victories there has been by more than six points.
Colorado at Nebraska: The No-Trophy/No-Name Rivalry
The roots of the Colorado-Nebraska rivalry have been intense only since the mid-1980s, when former Colorado coach Bill McCartney placed extra importance on the game by making the Nebraska game the Buffaloes' most important rivalry. In 1982, McCartney had office secretaries answering incoming calls the week before the game with "Beat Nebraska." During that time, the Cornhuskers were in the middle of an 18-game winning streak in the series.
It became more important in the latter stages of the Big Eight, when the game often determined conference championships. From 1994 through '96, both teams were ranked in the top seven when they met.
That history helped it earn the coveted Friday-afternoon slot after Thanksgiving, where it has remained every season of the Big 12's history. The Cornhuskers hold a 46-18-2 series lead.
Current Colorado coach Dan Hawkins has downplayed the rivalry at times, but still had a zinger for his foes during the difficult 2-10 2006 season that started his coaching tenure. During a homecoming rally that first year, Hawkins told the crowd, "The worst days as a Buff are better than the best days as a Cornhusker."
Both teams will have a lot to play for this season. Nebraska can wrap up a likely trip to the Gator Bowl with a victory. And Colorado needs to notch its first road triumph of the season in order to become bowl-eligible for the second straight season. Colorado could be headed to the Independence Bowl or the Texas Bowl with an upset Friday.
Tim Griffin is ESPN.com's Big 12 football blogger. He may be reached at firstname.lastname@example.org.