The Fairfield, Ohio post office [a branch of Hamilton], north of Cincinnati, did something nice for its community's 50th year of incorporation: it had five large murals painted on its front and side, documenting some aspects of the pre-/history of the town.
Here are a few more images [click the thumbnails to enlarge]:
Another interesting thing about this office: It features a drive-through stamp window! It's no longer in use, but this was the third I've seen (after Laconia, NH: Lakeside Station, and Moultonborough, NH).
P.S. Those 'bricks' you see on the side of the building? They're actually painted on.