Daniel writes –

“You know all those RGB LED projects with microcontrollers and power transistors and stuff?

Well, this is the almost-too-easy version.

Modern two-pin RGB LEDs are cheap and pretty, and they don’t need so much as a current limiting resistor, if the input voltage is right. Just hook ’em up to about three volts and away they go.

It’s thus trivial to install them in cars, computers, flashlights… you name it.”Link & video.