If you have ever wanted a game that is easy to pick up but surprisingly hard to put down, Slope Game might be exactly what you are looking for. It is a fast-paced 3D endless runner where you guide a rolling ball down a winding, ever-faster track. There is no finish line, no level select, and no long tutorial. Just you, a ball, and a path that keeps getting more demanding.
If you want to try it yourself, you can find the browser version at Slope Game.