Spenny ate Kenny's vomit (believing it was his own).
The episode was about trying not to vomit. Making Spenny eat what he thought to be his own vomit was great.
Kenny drank non-alcoholic beer and consumed a 'magic powder' to convince Spenny that it was allowing him to drink more and was not making him drunk.
16th Oct 2005 / Season 2 Episode 01
Kenny drank non-alcoholic beer and consumed a 'magic powder' to convince Spenny that it was allowing him to drink more and was not making him drunk. Once Spenny had passed out from excessive drinking, Kenny made himself vomit to make Spenny think he threw up. (Rules of the contest stated that if either vomited, they would be disqualified.)
Endurance competitions entail lasting longer than the other guy. They include competitions when the other guy might get caught or break a rule first, as they didn't endure longer.
OG Commentary
During this original commentary with Kenny and Spenny, we get a great amount of insight into Spenny's history with alcoholism.
Discussing the editors of the show and some of the crew and extra people, like a man who had his finger in Spenny's bum.