Traditionally, the cast is given clues to guess the identity of the episode's guests, and once the guests appear and are introduced, they and the cast are given a set of puzzles to solve.
Kureyon Shin-chan
This Hour Has 22 Minutes
Eureka
This Is England '88
Undeclared
Two Guys and a Girl
Kourtney & Khloé Take the Hamptons
TURN: Washington's Spies
Sugar Rush
Star Trek: Enterprise
The Corner
Ordeal by Innocence
The Hot Zone
Doctor Who
Zendeh Rood 98
Brass Eye
Hardball with Chris Matthews
Barefoot in the Park
Paco y Veva