Minecraft sometimes has a yellow tagline that says "Closed Source!" Erik (age 6) asked me about it. "What's source?" It's the instructions to the computer that tell it how the game works. "Why is it closed?" They want to be able to make it so they can sell it and that people can't make changes and sell it themselves. "So we can't figure out how the game works?" Nope. "Not even on our own computer?" Nope. "They're mean! That's the BORINGEST!"