Dad is a Hawkeye fan (no connection to the school at all), mom doesn't give a rip about sports, stepdad is a Nebbie fan (he was born and raised there, went to undergrad and grad there, I cut him some slack).
My dad took me to most home EIU football games when I was younger, and some men's and women's basketball games. I never really thought about ISU until around college-search time when I realized the people in my class going to EIU were mainly d-bags that I didn't want to associate with. And ISU has one of the best programs in the nation in what was my planned major (things have changed there), so it went to the top of the list. Never even visited EIU--miffed dad a bit, but he got over it.
My dad even bought Cy's Pack season tickets last year and dons an ISU hat and sweatshirt during the games! During the EIU game last fall I let him wear an EIU hat and ISU sweatshirt, but hey--he does help with tuition! And the 3 of the 4 games he made it to last year, we came out victorious so we encouraged him to buy Cy's Pack again this year.
Sorry for the lengthy novel.