Mysterious Benches Show Up In Ann Arbor, Michigan

(Ann Arbor, MI) -- There's a mystery sitting on the minds of people in Ann Arbor, Michigan.  

Wooden benches with whimsical puns are showing up in front of businesses in the city.  

One has the words, "sit happens," on it while another reads, "bench marks the spot."  

Nobody knows where the benches are coming from or how many there are, but one has become a favorite among the business owners that reads, "the butt stops here."