This puzzle is based on a fun pub game, known as the Green Room. There are quite a few other, similar games that work on the same principle.
The game works best if a small number of people know the code, and another small number of people don't know the code. People in the know will say things like "Item A can be taken in the Green Room, but Item B is not allowed".
By listening carefully those not in the know attempt to work out the code. Someone might think they've worked it out and they make their own statement, and are told is it's correct. If they're right they join in making statements; if not, listen more carefully.
Gradually, more and more people work out the code, and the game ends.
So the puzzle is, based on the following three statements, which of the two items below is allowed in the Green Room?
You can drink Beer in the Green Room, but no one drinks Lager.
Walking is strictly forbidden in the Green Room, but Jogging is encouraged.
People snack on Pecan Nuts in the Green Room, but Peanuts are banned.
Which of Snooker or Darts is played in the Green Room?
The clue is the double E in Green and the double O in Room, and the only things allowed have double letters - so Snooker is played in the Green Room.