There are some games that stand out on mobile. Not due to the quality of graphics nor the depth of gameplay. Rather, it is simply due to how ridiculous yet addicting a game could be by being extremely hard. Hate it or love it, Flappy Bird is a must-have game on your phone. No, not because it's the greatest game but the sheer challenge reels you in. Oh, and it's free.

Flappy Bird is a mobile game for iOS that has been countlessly mentioned across various gaming sites and social networks (especially Vine), which have helped this small title by Dong Nguyen climb up the charts in the App Store. It is a combination of Nintendo-style, Mario graphics including the familiar green pipes and an awkward looking bird. Players are tasked with flapping their way successfully between the green pipes.

Flappy Bird is an endless flapper, players will tap to flap the wings and slightly propel the bird vertically. However, the bird will drop quickly due to gravity by holding off. The goal is to pass through as many gaps -- very narrow gaps -- between the vertical green pipes. You will gain a point for each gap you have successfully cleared.