My ring is built into a 3D-printed shell I designed.
It has 7 of the same RGB LEDs and runs a ported modified version of the code for my RGB glasses. There's a small momentary switch to change modes, and it can run any mode the glasses can except those that use motion or sound input. This ring runs from a similar tiny lipo cell, but I wore it on my wrist with a wire out to the ring.
Both of these were exercises in ridiculously small wiring--I had to use 34AWG to connect to the QFN microcontroller. My motivation for these was in part just to test how small I could successfully solder. Here's the code for hers and his