Heck, why not put in a whole library?
The residents of a small village in Somerset have done just that. When their “Giles Gilbert Scott K6 design phone box” was threatened with demolition, the 800 people of Westbury-sub-Mendip defended its honor by buying the box and converting it to a lending library. A local councilor says, “This facility has turned a piece of street furniture into a community service in constant use.” He's not kidding; the library is open 365 days a year, 24 hours a day. (Collect calls not accepted.)