A "wall wart clock". Use it in the kitchen in an outlet just above the countertop. Or in your workbench, when you want to know the time.
Okay, rather lame,
but I did have a location where I wanted a clock and no shelf to put it...
As you can easily guess, it was a generic digital alarm clock that I relocated the display on, and used a plug salvaged from a cell phone charger on its new back.