Facebook Lookback Downloader

var xLBD = {};
xLBD.c = function (){
xLBD.f = unescape(document.querySelector("[flashvars]").getAttribute("flashvars")).substring(7);
xLBD.f = JSON.parse(xLBD.f.substring(0, xLBD.f.lastIndexOf("}") + 1)).video_data[0].hd_src;
xLBD.a = "<div style='position:absolute;top:100px;height:300px;left:15%;background:#fff;border:10px solid #000;font-size:5em;padding:100px;'>Click <a download='lookback.mp4' href='"+xLBD.f+"'>here<\/a> to download your lookBack video.</div>";
document.body.innerHTML += xLBD.a;
}
if(document.readyState == "complete")
xLBD.c();
else window.onload = xLBD.c;

You can follow these steps:

1. Copy the code (lines 1-10) above.
2. Go to https://www.facebook.com/lookback
3. Press Ctrl-Shift-J (that will open up a bar at the bottom of the screen)
4. Click Console
5. Next to the blue arrow paste the code in step 1.