Scrabble
Each letter has a number of points. Letters worth more points are less common. For example, common letters such as E, T, and A are worth one point, while uncommon letters such as Q and Z are worth 10 points.  There are also two blank tiles which can be used for any letter. These are worth zero points. A player must say what the letter is when they place it on the board. For example, a player might place the tiles "C", "A", and a blank tile on the board, and say the blank tile is a T. This makes the word "CAT". For the rest of the game, the blank tile must be used as if it was a T.