This wearable LED glow ring is a great way to get started with the Pro Trinket. It has a LiPo power source, 3 NeoPixel LED's, and a power backpack to charge passively via USB. All the printed components can be generated in a single build without support material.
Before getting started you should take a look at the Adafruit guides that cover the tech we'll be putting inside this ring.
This is also an intro to mold making and casting using a 3d printer, as the silicone glow crystals are cast out of a mold that prints right along with the ring components.