Prepare for unexpected vet bills
We don't mean taking the biggest road trip, but more so a road trip to see "the biggest" of several quirky monuments. North Dakota has both the largest buffalo (in Jamestown) and the world's largest Holstein (in New Salem). A heater-blasted road trip can be a great way to spend a few hours, especially when you get awesome pictures to boot!
Just because they aren't the world's largest doesn't mean they're not worth the trip and they look that much cooler against a stark, snow-white background. The Enchanted Highway Sculptures in Regent offer a ton of interesting figures to look at from giant people to animals and even a cross-section of a house!