For those who do not understand why Purdue is out most hated rival:
Iowa and Purdue were literally the last two schools left when they were deciding the Legends and Leaders rivalries/protected crossovers.
1. Michigan and OSU, obviously
2. Minnesota and Wisc, play for an ax, one of the longest running series in football
3. Nebraska and PSU, the new kids on the block, make up for 1994's split National Championship
4. NW and ILL, battle for Chicago
5. MSU and Indiana, basketball rivals so why not football too
Who we got left?
Iowa and Purdue
Sounds good, lets call it a day.