[picture of C-47 with pinup-looking person in the door--don't know why it isn't showing properly]
Airborne! All the way!
Bottom five is an interesting topic. I haven't put as much thought into it, but as a quick pass: Colorado and Syracuse stomping on the Badgers to begin seasons (1994, 1995, and 1997, I think), and Georgia to finish it in January 1998. Abbredaris fumbling the ball against Oregon late in the Rose Bowl (heck, three of the last four Rose Bowl losses, TCU and Oregon x2--the Stanford one didn't bother me that much). The OSU beat down in the 2014 B1G championship game. The collapse against Penn State in the 2016 B1G championship game. The collapse and loss to a terrible Michigan team in 2008. Some of the fumbles against Northwestern stand out (1996, 2000, 2005, 2009, 2018--I don't even know if all of those were fumble games, but they all feel like it because they were against Northwestern).
So those would be the categories: embarrassing national blowouts, Rose Bowl Failures, B1G championship failures, Northwestern, and the most pathetic loss to Michigan that I can remember.
That 2004 Purdue/Wisconsin game is on my (pretty long) honorable mention list for favorite memories. That was a crazy, brutal finish for Purdue.