In a soccer game you might see a ref blow his whistle and call a player over and pull a card out of his shirt pocket.  The ref always carries 2 colored cards in his shirt pocket, both meaning 2 different things.  He or she always has a yellow card, which is pretty much a warning card, and he or she always has a red card that is more serious.  When someone on the team is acting unsportsmanlike, using foul language, or delaying the restart of a play the ref will call the player over and hold up a yellow card.  The yellow card means that the player has to go out for a few seconds and he or she can’t get another yellow card or else the ref will give them a red one and they’ll be ejected from the game.  If the ref sees serious fouls, violent conduct, spitting, or using your hands to prevent a goal, he or she will give you a red card.  The red card means that you’re out of the game and your team will have to play one man short.  If a coach is being loud and unsportsmanlike he or she will also get a red card and will be ejected.