I had almost the EXACT same thing happen!

ORD-MSP flights full. Spring Break

Living in EAU, but we had a car at my parent's house at MSP.

Decided to take wide open EAU flight, figure out how to get car another time.

Saw one of my professors and a coworker were on flight as well.

On approach to EAU, pilot said they couldn't land, would try again or divert to MSP.

Tried again, diverted to MSP. Told that if we couldn't make it to EAU next time, the plane would go back to ORD.

Begged flight attendant to let me off at MSP. Didn't take much, she was just thrilled to have someone happy about the diversion. Professor's daughter's birthday party was that day, and he did not want to go back to ORD, so he went with us.

Car was at parents' house, couldn't find anyone to pick us up at the airport (parents left town). Professor paid for the cab ride to my parents' house in exchange for the ride to his house.

Made it home early that afternoon!