Combining two of Channel 4's favourite shows means viewers get to play along, a plus for both quiz and comedy fans alike. Jimmy Carr hosts the famous words and numbers quiz, with `8 Out of 10 Cats' team captains Sean Lock and Jon Richardson playing against each other. In each episode they are joined by guests from the world of comedy and entertainment, including Alan Carr, Lou Sanders, Johnny Vegas and more. Dictionary maven and adjudicator from `Countdown', Susie Dent, also takes part, joined by a different guest for each episode. Also, mathematician Rachel Riley takes on her usual `Countdown' role.