When a player logs into my Minecraft server, the associated folded paper avatar lights up: blue-green as they log in, white while they're online, red just after they sign off.
Avatars
paperminecraft.com or pixelpapercraft.com generates templates, given any Minecraft character's nickname.
A diffuse RBG LED in the back of each avatar's head illuminates the character and changes color to signify status.
Circuitry
A Teensy 2.0 controls the LEDs based on status information sent over its emulated Serial connection.
Since the Teensy has only 7 PWM (dimmable) output pins, each LED's green and blue channels are tied together to a PWM pin, and each LED's red channel is tied to a regular digital output. A PWM driver could have allowed full color output, but at the cost of slightly increased software complexity.
The LEDs are connected to the microcontroller via resistors (150Ω for G and B, 330Ω for R) with simple hookup wire.
The hookup wire's stiffness supports the avatars.
Software
A Python script queries a Minecraft server for player status, then sends a list of online players to the Teensy. The Teensy runs an Arduino sketch that translates the list of names to output pin settings, controlling the LEDs.