In our home game, players will sometimes reveal a card with two players remaining in the hand to entice the other player to call or fold. For example, with 3 clubs on the board after the river a player may reveal the ace of that suit while the other player is considering what to do.
While playing texas hold'em, is it against the rules to reveal one of your own hole cards during play?
Many tournaments, such as the WSOP and WPT, will declare a hand dead if it is exposed. In cash games or private games, it will depend on house rules, but it is generally allowed.
Interesting, I've never seen someone try to do this - home game or not. My read is this would be up to the host (or Casino) as it's not explicitly denied as far as I can tell. Consulting Robert's Rules:
General Poker Rules - Irregularities, #12:
Procedure for an exposed card varies with the poker form, and is given in the section for each game. A card that is flashed by a dealer is treated as an exposed card. A card that is flashed by a player will play. To obtain a ruling on whether a card was exposed and should be replaced, a player should announce that the card was flashed or exposed before looking at it. A downcard dealt off the table is an exposed card.
There's nothing called out in the Hold-em section prohibiting a player from doing this.
I would say this was unorthodox behaviour, but I've rarely observed it to be against the rules. Robert's rules suggests the hand would still be live, as discussed in @Al G's answer.
There is, or ought to be, an exceptional case that is not specifically covered by Robert's Rules: it should be against the rules to flash your card (accidentally or deliberately) to some players without making the card clear to all players. That case would essentially be collusion.
If anybody (player or dealer) flashes a card, all players should have the opportunity to see it.
