I'm riding home, and I'm just about home (can literally see my house), and my bike is like "Hey, wanna hear a joke?", I tell my bike that I'm busy riding, and can't concentrate on jokes right now. My bike starts telling the joke anyway, it says "Have you heard aobut the guys chain tensioner than exploded? It goes like this...BAM!!!". My back wheel locks up, and I slide on the road a bit, almost falling off. Not sure what happened, the plastic wheel on the chain tensioner disappeared, and my engine was on a horrible angle. I took the chain off, and walked it a minute to my house. Nothing seems broken, none of the studs are damaged, I loosened them/straightened the engine up. I replaced the wheel on the tensioner with an old one I had laying around. Bikes don't tell funny jokes.