Okay, I remember there were 4 or 5 teenage kids...and they would always make fun of a chubby kid and they dared him to do something - they were on boat and I think the dare was for the kid to jump into the water (or get something)...and he didn't know how to swim but did it anyway and the other kids saw he was drowning and didn't do anything to save him and the kid died.
They did have a camcorder and the whole thing was recorded...

I remember seeing this in a commercial a loooong time ago and I just remembered about it and wanted to see it. Can you help me out?