What's a Tell?

I played in a new poker game last night.

I won, which is nice.

A "tell" is something you do inadvertently, even subconsciously, the tells other players (at least those paying attention) something about your hand. It's usually very subtle.

You might remember a MASH episode where everyone realizes that Major Winchester whistles when he's got nothing.

Well, here's a freebie, if we ever play poker: Pokerface in DC got a good hand last night and promptly spilled his beer all over himself.

That's a tell.