Food poisoning.
Visiting Madison, WI where my girlfriend went to undergrad. After a community nonprofit event, we were both a little hungry so she suggested one of her old grease pits from her college days on campus. It was 9:55p, 5 minutes before the kitchen closes (even though they are open until 11p). We order quick, taking in the hipster scenery and Midwest history. Our food arrives and it's your typical bar food, but we are here more for the nostalgia.
Now it is the middle of the night, we are both up, stomach twisting out of our guts, while we fight wave after wave of nausea.
It may be because we came in last minute before the kitchen closed? Regardless, this late night snack is putting a damper on our stay in WI.