Of the various teams that either we, or they want to call rivals, lets take a look.
OU - The history is there, at least till '96. Now it is every two years. OU doesnt consider us their rival either. They look at Texas as the rivalry game, with OSU second. Add in the fact that they have the last 4 of 5 games doesnt help our cause of calling them a rival. This may have been our traditional rival, but it is not one to talk about for anything more than nostalgia anymore.
KU - two wins in 30 years? Not a rival, there has to be wins a lot closer and more heated than that.
KSU - Last season was the first time sence Osborne left that we won in Manhattan. In the Big 8, no they were more or less a whipping boy. But in the Big 12 era, they have been one of the games that has tended to be for the rights to the champ game. The absolute hatred of the fan bases against each other is another factor. Weather some want to admit it, this has become a rivalry game. It may not have the long term history, but it has the more recent parts, and looks to continue into the future.
CU - This is another game that has had alot to say about who goes to the champ game. It is another case of the fan bases absolutly hating one another, on the CU end to the point where the student section got ejected in our last trip to Boulder. While they were down last year, and likely this year and the next, it is a type of game where players get up for it regardless of if it matters or not. Rivalry.
MU - While it may be possible for something to develop here, it certainly isnt yet. The games tend to be close, but there isnt the passion for it like there is for other games. Hell, this is the team i sometimes cant remember being in the Conference.
Rivalry is such a loaded term in football. Some only want to remember the older things and pass off the newer ones as just short term, or that they just hate that team. Hating a team you play every single year, and where the games tend to be the ones for the marbles are what rivalries are about. OU used to be the team. But in the post Big 8 world, it has to be CU and KSU.