He's Too Sexy for His Fat - S2-E17
Factual error: Peter starts helping Chris work out, and in the second part, Chris is trying to do pull-ups on a bar outside. In the first shot, there is an unlit campfire under his feet, and he even appears to be standing on it. In the next shot, Peter walks around him and Chris starts lifting. Peter says, "Feel the burn," and sprays fuel on the campfire spot. Suddenly, the fire is lit, without Peter having actually lit it. Just spraying lighter fluid on wood doesn't start a fire. (00:09:30)