Of all the factors that set college football apart from the NFL, rivalries are probably the one college fans site most often in defending their preference. Season-ending games between decades-long rivals always bring out the cliches: The records truly can be thrown out, as emotion, both from the players and fervent home crowds, can be an equalizing factor.

Not all this week’s rivalry games have a direct effect on the Bowl Championship Series, but the games in Ann Arbor, Auburn, and elsewhere will still be played at a higher level of intensity than any others this year. USC, the consensus no. 1 team in the nation, must wait two weeks for its rivalry game against UCLA, but the Trojans have an interesting non-conference match up against Fresno State, perhaps the best team from outside the six leagues with automatic BCS bids. Here’s a preview of some of Saturday’s key games:

NO. 7 OHIO ST. (8-2, 6-1) AT NO. 15 MICHIGAN (7-3, 5-2)
(Saturday, 1 p.m., ABC)

NO. 4 PENN ST. (9-1, 6-1) AT MICHIGAN ST. (5-5,2-5)
(Saturday, 4 p.m., ESPN)

The Big Ten schedule sets up nicely Saturday as Michigan and Ohio State, two of the teams that still have a chance to gain a share of the conference title, will be nearly finished with their contest when Penn State, the only team that controls its own destiny for the conference’s automatic BCS berth, kicks off against Michigan State.

What makes the Ohio State-Michigan rivalry perhaps the greatest in all of sports is that it’s so evenly split. Michigan enjoyed a period of dominance against former Ohio State coach John Cooper, but current Buckeyes leader Jim Tressel has won three of four games against the Wolverines, shifting the pressure squarely onto the shoulders of Michigan’s Lloyd Carr. Over the last 50 years, the series is tied 24-24-2, with nearly every one of those contests playing some part in determining the conference crown.

Ohio State enters this year’s game on a tremendous roll, and can win the conference outright with a win and a Penn State loss to Michigan State. A Penn State loss combined with a Michigan win would create a three-way tie atop the conference, and the Wolverines would claim the BCS bid thanks to head-to-head wins over both Penn State and Ohio State.

Michigan’s fate may be tied to the health of tailback Mike Hart, who is expected to return after missing two games with a sprained right ankle. While Hart’s backup, freshman Kevin Grady, is a gifted straight-ahead runner, Hart spreads the field from sideline to sideline and provides an important safety valve for quarterback Chad Henne.

Henne has shown improved accuracy during Michigan’s current four-game winning streak and has taken better care of the ball. Avoiding turnovers will be key against Ohio State’s speedy, ball hawking defense.

Ohio State’s offense goes as quarterback Troy Smith does. Smith burst onto the national scene with a huge game in an upset win over Michigan last year, and he’s played the best football of his career during the Buckeyes’ last five games, all wins. Scrambling quarterbacks have been an Achilles’ heel for Michigan in recent seasons, but the Wolverines have improved vastly in that category this year, posting wins against mobile quarterbacks from Michigan State, Penn State, and Northwestern.

Ohio State is a rare road favorite in this series, but getting off to a fast start and neutralizing the crowd will be crucial. This should be a low-scoring hard-hitting affair, played on the competitive edge as most rivalry games are.

Penn State shouldn’t have much trouble with a Michigan State team that has completely fallen apart since starting 4-0, but stranger things have happened. If the Lions take care of business in East Lansing, Joe Paterno will be rewarded with his first conference title since 1994 and a BCS berth.

NO. 8 ALABAMA (9-1, 6-1) AT NO. 13 AUBURN (8-2, 6-1)
(Saturday, 3:30 p.m., CBS)

If not for Alabama’s overtime loss to LSU last week, which ceded control of the SEC West to the Bayou Bengals, this might be one of the most hyped Iron Bowls of all time. Of course, this game would be a hyper-competitive hate fest even if both teams were winless. This rivalry extends beyond the field, with a long history of boosters from one school ratting out the other to the NCAA for recruiting violations.

On the field, Auburn has won three straight in the series, and has steadily improved all year. Quarterback Brandon Cox may have reached a turning point last week, delivering a 62-yard pass on fourth down to set up the game-winning field goal against Georgia.

The Tigers will attempt to run the SEC’s leading rusher, Kenny Irons, into the teeth of an Alabama defense that is one of the nation’s best. Alabama has ridden that defense to grind-it-out, defensive wins ever since receiver Tyrone Prothro was lost for the season early in the season, but that style finally caught up to the Tide against LSU. The defense did all it could to keep Alabama afloat, but the Tide was too empty of offense to overcome consistently poor field position in the second half.

If Alabama is to win on the road, quarterback Brodie Croyle must have time to throw downfield to loosen up the Auburn defense. Alabama has far surpassed expectations this year, but will end the regular season with back-to-back losses unless the offense can balance the defensive effort.

NO. 17 FRESNO ST. (8-1, 6-0) AT NO. 1 USC (10-0, 7-0)
(Saturday, 10:15 p.m., FSNY)

Fresno State coach Pat Hill, a former assistant with the Cleveland Browns under Bill Belichick, has built the Bulldogs into perhaps the most-successful non-BCS league program in the nation by showing no fear. Hill’s motto is “anybody, anytime, anywhere,” and this game against USC is the latest example of the type of scheduling that has put Fresno State on the national map.

Do the Bulldogs have a chance against USC? Fresno’s defense, though solid, probably can’t cope with Matt Leinart, Reggie Bush, and USC’s galaxy of offensive stars for 60 minutes, so the Bulldogs must attempt to run the ball with Wendell Mathis and keep Leinart and company on the bench.

Still, USC’s defensive vulnerability is against the pass, so look for Fresno quarterback Paul Pinegar to attempt a few deep balls. Fresno has the mentality to make this one interesting, at least into the second half.

Mr. Levine is a writer for FootballOutsiders.com.