The Brain Tickler is an arcade question game in Pajama Sam in "No Need To Hide When It's Dark Outside".
This mini-game is first accessed when the player clicks on Wink & Blink (whose faces are not shown yet) for the first time.
After some dialogue between the doors and Sam, the doors will ask Sam if he can play this game to see if he knows anything.
In the game, Sam has four categories to choose from. Three random ones and "The Land Of Darkness". In order to answer the fourth one, you have to find out what the meter says in the mines or what color the garden flowers are. But sometimes it changes. Sam also has to complete this game to get past Wink & Blink to get to the other side of Darkness' house as there often items there that Sam must use to retrieve his things.
Sam, at any point, can take a break from the game by clicking the arrow on the bottom right of the screen if he has not completed it yet (which should be done if the player doesn't have the information necessary to answer the Land of Darkness question). Wink & Blink will automatically pause their game until the player clicks on them, at which they will restart the game.