Poi is a type of performance art originating with New Zealand’s Māori people in which the performers dance with weights on strings — also called poi. In recent years, poi has grown in popularity in the west, particularly in the EDM (Electronic Dance Music) scene. As you’d expect of the EDM scene, the poi are often equipped with glowing lights. If you want to build your own, MilanDer has a tutorial covering how to make a pair of RGB LED glow poi that are remotely controlled.
As MilanDer points out, you can purchase commercial LED-lit poi already for very little money. But this adds remote control functionality, as well as the satisfaction of making something with your own hands. The remote control is done using an IR (InfraRed) receiver, which can be programmed to respond to commands from any traditional remote. Each poi has 10 Adafruit NeoPixel-style individually-addressable RGB LEDs that can be programmed to change color in various animations.
Those LEDs are controlled by an Arduino Pro Mini, but will work with just about any development board. Power comes from a small 1000mAh LiPo battery through a TP4056 LiPo charging circuit and 5V boost converter. You will need to setup the code to respond to the IR command codes from your specific remote control, but that information is easy to find with a simple Arduino sketch. After wiring up the components and uploading the provided code, you can 3D-print the two pieces of the poi’s shell. Then just attach the strings, and start swinging!