Today the Big Brother 2013 housemates will be taking part in a twist on the classic game of Prisoner's Dilemma.
Each of the remaining housemates will be competing for a unique prize, but only some of them will actually win.
Up for grabs for each housemate is:
CALLUM: A romantic dinner with a housemate of your choice.
DEXTER: A romantic dinner with a housemate of your choice.
GINA: Laundry service for a week.
SOPHIE: Luxury beauty pack.
HAZEL: Luxury chocolate hamper.
JACK: Half a birthday bash.
JOE: Half a birthday bash.
CHARLIE: Luxury cheese and wine hamper.
SAM: Sports trainers.
DAN: Luxury pamper kit.
But the housemates have been split into pairs:
Dan vs Joe
Gina vs Hazel
Dexter vs Callum
Sophie vs Charlie
Sam vs Jack
Each pair will take part in a game of the Prisoner's Dilemma.
The housemates in each pairing will stand back to back, with a box between them containing their prizes.
A timer will start counting down to 10 seconds where they will have to decide whether or not to smash the box.
If both smash the box, they both lose, if they both fail to smash the box, they will share a small treat, but will not get their main prize (above).
Only if one housemate in the pair smashes the box and the other doesn't, will the housemate who smashed the box win their reward.
Check back later to see how they get on!