Google's Pixel Chromebook has an Easter egg built into the software that triggers a hardware event. The event is a light show of the available LED on the laptop. This particular egg is a take on the so-called Konami Code; a sequence of key presses that enabled extras on some old Konami games.
Initiate the egg with the directional keys:
As this is software based, it might not survive future upgrades.
Picture from www.wired.com.