Flappy Bird, the phenomenon of a game, has been pulled from the App Store by the developer Dong Nguyen. But, if you previously downloaded it you can still install it from the list of previously purchased items in the App Store, here's how.
• Launch the App Store on the device Flappy Bird needs to be installed on.
• On iPhone: Go to the updates tab, tap on Purchased at the top of the list.
• On iPad: Go directly to the Purchased tab.
• In the search bar, type Flappy Bird to narrow down the list of available apps.
• Click the iCloud download button.
• Flap, flap, flap your life away!
So Flappy Bird is gone, but not forgotten. Enjoy!