Line Rider is a game that is basically the Prince of "Time Wasting" online. Years ago, it's what I played during my lunch break while eating pizza. I haven't heard or played "Line Rider" in forever, but when someone showed me this video of a Line Rider basically hitting each note of "In The Hall of the Mountain King" I had to push play.
So you're asking before you push play..."What's 'In The Hall of the Mountain King'?" Oh just a very intense classical song by Edvard Grieg that you've heard a million times.
Seriously, from the middle of the video until the end, I was at the end of my seat!
And if you want to play "Line Rider" just go HERE