'In the Sack' is a couples' special game. All the couples are split up into men and women. The men all start behind a sheet on one side, and the women all start behind a sheet on the opposite side.
When the starting whistle is blown, everyone has to run out and try to find their partner. Once a couple has been reunited they have to go and lie on a bed.
There are only 55 beds, which isn't enough for every couple. Only one couple can be on any one bed, so the contestants have to move quickly to ensure they grab one for themselves.
When all the beds are filled the whistle is blown. All the couples on a bed go through to the next round, while the others that are still standing lose and are out.