To
bet everything you have in a
poker game. Allows a player with less money than another player to complete a hand he would not have had enough money to participate in the
bet/
raise/
re-raise rounds with. Limits your potential
upside for the game though.
This causes most of the famous scenes in the
World Series of Poker where one player moves his
enormous stack of chips into the pot saying "I
go all in", the other player does likewise with his chips and says "I
call, what ya got?".