Monument Valley is one of those games you have to play to truly appreciate. It's a puzzle game with a very MC Escher feel, it's a litte Zen, and now it's totally free. The game is usually priced at US$3.99, but right now it's available for free on Apple's App Store. Monument Valley earned a Best Of award from Apple in 2014, and TMO's Melissa Holt gave it a thumbs up, too. If you haven't played it yet be sure to pick up Monument Valley now before the price goes back up.
Check It Out: Monument Valley Free for iPhone, iPad