We had a guy in a bar league that got caught cheating... at FREE BAR POKER! LOL. I knew and played with the guy but wasn't there the night he was caught.
It was self dealing bar poker, so he would hold the deck after he dealt the flop for example, and swish the corner edge of the cards with his thumb, in a downward motion I believe. Apparently someone stood behind him one night and saw while he was doing that he was allowing himslf to see the top few cards. He ended up confessing and everything once he was caught and was banned from the league. He never played in any of the local home cash games or anything before that(or after), so nothing bad happened to him à la street justice or anything.