The Wheel Inn in Sedalia, Missouri sells the one-of-a-kind guber burger. The guber burger is exactly the same as a regular burger except for one catch- it has slathered with peanut butter. If you're in or near Sedalia, stop by this classic American drive-in.
Charles P. Pierce wrote a short review of this restaurant in his article "16 Things to Do Before Labor Day." (Stopping by this drive-in is listed as number five.)
Find the location via Google Maps.
Last year, the location of this restaurant changed. You can read all about the old location at the Neato Coolville blog.