Finally, you can now play Flappy Bird on 1977's Apple II computer. It's the work of Dagen Brock and can be downloaded for both 5.25" and 3.5" floppy disks. Whatever they are...
If, for some reason, you don't have an Apple II and a floppy disc spare then you can always play it via a web emulator. It actually turned out to be a challenge for Brock who inexplicably decided it had to run at "60 FPS on a 1MHz Apple II", a target that took him six weeks to achieve.