Have you ever jumped on something as you're moving through the real world, and heard that Mario bouncy sound in your head? Or maybe seen someone acting like an NPC when they're a real person? Maybe you know that the first real "in-app" purchase was actually a weapons store in an arcade game version of Double Dragon 3.

Wherever you go in the real world, you can find signs of the influence of videogames. But you have to know where to look. That's why Endless Thread and 99% Invisible are launching a new limited series together called Hidden Levels.

Today Roman Mars and Ben Brock Johnson kick off the series with a little preview of what's coming.