So Facebook engineers are geeks too. Indeed, if you use the classic cheat code "Up, Up, Down, Down, Left, Right, Left, Right, B, A, Enter, Right Clic", a Lens Flare effect will appear in your Browser. Ok, it's useless, but hey, it's fun!

Oh and to remove the effect, simply close the page and open a new browser.

↑ ↑ ↓ ↓ ← → ← → B A