The holiday season has officially begun. As Christmas carols and fake snow become part of your routine, you might want to take a break from the holiday cheer and enter a different fantasy world. Fortunately, technology has just the remedy for this kind of situation: virtual reality.For full immersion in the land of pixels you only need a smartphone, headphones, and a headset. Remember you can always make your own, Google Cardboard gave us the basic idea, and there are several tutorials that can show you how.All set? Whether you have iOS or Android here are five free apps to lose yourself far away from the Drummer Boy:1. YouTube[caption id="attachment_43479" align="alignright" width="300"] Visit Paris with Youtube. Photo: YouTube[/caption]You most likely already have this app on your phone. Thanks to the increasing number of 360-degree cameras, there is a good amount of content you can explore in augmented reality. Look around; really look around. This is a great way to start testing those DIY headsets.2. WithinA storytelling app with content that is both diverse and interesting, Whitin features investigative documentaries and fiction. All of the content found in this app is original, so it is worth it to take a look. Enjoy stories from The New York Times, Vice Media or lose yourself in an immersive music video.3. Zombie Shooter VROnce more, Earth is overrun by zombies due to catastrophe, and it is your turn to kill them. No controls needed, just look and kill. A good game to let out some steam caused by the extra traffic the season brings.4. OrbulusOrbulus is a photo viewer that allows you to walk the world through photo spheres. Ambient sounds provide the right amount of credibility to your mountain hikes or wining and dining in Europe. It is a good option to consider to rest your head from motion-sickness.5. Romans From Mars 360[caption id="attachment_43475" align="alignright" width="300"] Screenshot from Romans From Mars 360. Photo: iTunes[/caption]This game is exactly as cool as its name indicates. As a Roman solider it is your duty to wipe out the alien enemies with your vast arsenal of lightning and fire. Graphics are fun in-game options that make the game hard to put down. Also, no controls are needed; just aim and shoot in the name of Jupiter.