There have been a few unusual football seasons over the years. 1973 was unusual because of all the undefeated teams at the end of the year.
1981 was an odd year as well but only because it appeared that nobody wanted to be #1.
Michigan started the season ranked #1 in the polls, but they blew that really quickly losing in their first game to an unheralded Wisconsin, 21-14.
Notre Dame was the new #1, but they lost the first weekend they were at the top to Michigan. 25-7
Oklahoma should have been #1, but they gave it to USC instead and in a showdown between #1 and #2 USC beat OU with 2 seconds remaining 28-24.
USC stayed at the top at least longer than the time it took to move them up, but lost 2 weeks after the OU win to unheralded Arizona, 13-10.
Texas, on the strength of a sound beating of rival Oklahoma, took over the top spot. That lasted all of one week as they got blasted by Arkansas and Lou Holtz, 42-11.
Taking over for Texas was the Penn State Nittany Lions. That lasted 2 weeks before they were upset by unranked Miami, 17-14. Miami was not ranked but they had a really good team led by future Hall of Fame QB Jim Kelly. That was Halloween of 1981 and strange things have happened on Halloween football fields.
The Pitt Panthers were next. If you are a young person or you have a short memory, you may not know that the Pitt Panthers were a powerhouse back in those days and had some of the best talent in college football. Times have changed dramatically for the Pittsburgh Panthers but they were a force between about 1976 and the mid 1980s.
The Panthers stayed at the top for nearly a month before being absolutely crushed by in state rival, Penn State, 48-14.
The most unlikely team of all had risen from completely unranked at the beginning of the season to the #1 spot in the polls. The Clemson Tigers had made a miraculous climb and would finish out #1 and become national champs when they defeated Nebraska in the Orange Bowl, 22-15. They did it mostly with defense and one of defenders was freshman William the Refrigerator Perry of later Chicago Bear fame.
The 1981 featured 7 different #1 teams during the year and 8 if you count OU which some polls did.
In a year that nobody seemed to want to be the champions, the Clemson Tigers rose up and claimed the title.