It seems like just a simple building game. In reality, Mojang's "Minecraft" is a hugely popular, fully immersive and addictive fantasy world that you build yourself. The Pocket Edition version ($6.99) is very similar to the PC edition, which has attracted more than 12 million gamers around the world. Using the app you can create almost anything with your friends; cook food; fight with swords, bows or TNT; and even paint works of art. Once you start, we dare you to put it down.