Line Rider 2: Unbound

Line Rider, originally released in the fall of 2006, is an elaborate, yet accessible physics toy that features a character who sleds on any user drawn slope. Upon release, the game became an Internet phenomenon, attracting a cult following and ballooning into an obsession for many intrepid course designers. Line Rider 2: Unbound features the work of one of the most famous designers, TechDawg, who's creations can be seen at IRideTheLines.com. Source: The Game Website.