It would be sort of a modern take on the traditional hourglass idea.
Basically it's a clear or semi-opaque graduated cylinder divided into minutes, with each 5 minutes labeled and every hour as well. It sits vertically atop a low, wide base which houses the hardware. It slowly fills with some sort
of colorful (or colorfully lit) liquid. A disk or ring with a bright outer edge could float atop it and line up with the markings at the appropriate times. When it gets to the top of the cylinder (midnight), it empties and starts again. The cylinder itself would be bulbous on top to facilitate viewing from an angle above it (not directly overhead, mind you). A variety of lighting configurations come to mind, as well as mechanisms to force the liquid into the cylinder at a steady, reliable rate. For instance, it could just be a digital clock with a computer controlled pump mechanism of some sort, maybe a bladder compressed by a couple of boards squeezed together by a worm gear attached to a small dc motor of some variety fit for the task. If the cylinder were made of acrylic, then it could be molded to allow a light at the base of it to illuminate the important bits. Or you could use different colored lights that shine through for the different times of day (a dim, blue light for night and a bright, yellow light for day, and the like).
Or you could be a cheapskate and make a version that's just a bunch of LEDs glowing progressively through a stack of acrylic disks or whatever, which winds up serving the same purpose.
Or you could go hi-tech and just wrap a screen around a cylinder and make it all animated and neat-O looking.
BASIC IDEA: CYLINDER TIME DISPLAY VIEWABLE FROM PRACTICALLY ANY ANGLE with myriad possible ways to implement it.