according to Hoyle

- according to the rules (Hoyle wrote a well-known book about card games)
According to Hoyle we were not permitted to enter the convention site but in reality we were able to enter easily.

an ace in the hole

- something that you can use to gain an advantage (when playing cards an ace is face down so the other players in a card game can't see it)
The team had an ace in the hole and decided to use it when they brought out their star goalkeeper to play.

ante up

- produce or pay a necessary amount of money
We all had to ante up quickly in order to collect the money for our holiday.

call a spade a spade

- call a person or thing a name that is true, speak in plain language
I decided to call a spade a spade and tell our supervisor what was wrong with our workplace.

call someone's bluff

- challenge someone to show that they are not being deceptive and can actually do what they say they can do (from poker where one makes an opponent show his or her cards to show that they are weaker than they are pretending them to be)
My girlfriend always said that she didn't want to get married so I called her bluff and asked her to marry me. She said yes.

cash in one's chips

- to die (the chips in many gambling games are changed into cash at the end of a game)
After an honorable and fruitful career the judge cashed in his chips at the age of ninety years.

come/turn up trumps

- have a better performance or outcome than is expected (trumps are the playing cards that are chosen to be ranked higher than the others)
We entered the contest with little hope of success but our performance came up trumps which was a big surprise to everyone.

deal someone in

- include someone
I hope that my friend will deal me in on his new computer business.

be dealt a bad hand/deal someone a bad hand

- receive or give someone bad cards in a card game, receive disadvantages in something
The boy was dealt a bad hand when he was a child and always was at a disadvantage in his life.

follow suit

- play a card of the same suit, follow the example of another
The small university followed suit with the other universities and decided to raise their tuition fees.

force someone's hand

- make someone do something that they don't want to do at that time
The man threatened to quit his job so the company decided to force his hand and make him either continue or quit.

have an ace up one's sleeve

- something that you can use to gain an advantage (in a card game the ace is often the most valuable card and a cheater could have an ace up their sleeve to use against an opponent)
When the football players were ready to go on strike, the team owners had an ace up their sleeve and offered more money and stopped the strike.

have a card up one's sleeve

- have a reserve plan or a secret advantage
The man had a card up his sleeve when he went to the bank to ask for more money for his business.