If you have an old iPhone sitting around, Instructables user Purincess shows off how to build a custom frame that makes it easy to turn that iPhone into wall art or a clock.
The idea here is to make a frame using laser cutting, stack the phone inside, then set it up to display whatever you want, from artwork to a clock. While this guide concentrates on the dimensions of the iPhone specifically, there's no reason why you couldn't do the exact same thing for any old smartphone.
This older version of the post shows off a way to use MDF, which can easily be modified to fit any phone you want. If you're looking for a clever reuse for a phone that's otherwise sitting in a drawer, this is a fun way to give it a new life.
Reframe: turn old iPhone into wall clock or wall art [Instructables]