I'm pretty sure you guys have heard of this game, but I will post this anyways for the sake of discussion.
Happy Wheels is a flash game that can be found here.
It has different characters to play as, such as a homeless man in a jet-powered wheelchair. It has grotesque blood & gore, a level editor w/ the ability to share maps, and ragdoll physics. The goal of the game is to finish the level without dying.
If you haven't tried Happy Wheels yet, do so immediately.