Entertainment
Equipment varies with the game. Board games, such as Go, "Monopoly" or backgammon need a board and markers. One of the oldest known board games is Senet, a game played in Ancient Egypt, enjoyed by the pharaoh Tutankhamun. Card games, such as whist, poker and Bridge have long been played as evening entertainment among friends. For these games, all that is needed is a deck of playing cards. Other games, such as bingo, played with numerous strangers, have been organised to involve the participation of non-players via gambling. Many are geared for children, and can be played outdoors, including hopscotch, hide and seek, or Blind man's bluff. The list of ball games is quite extensive. It includes, for example, croquet, lawn bowling and paintball as well as many sports using various forms of balls. The options cater to a wide range of skill and fitness levels. Physical games can develop agility and competence in motor skills. Number games such as Sudoku and puzzle games like the Rubik's cube can develop mental prowess.
Lexiko
In 1931, Butts wrote a paper entitled "Study of Games." In his paper, he described three categories of games: board, number games using playing cards or dice, and letter games (or games that fell into more than one). He noted that, although the most popular games were of the first two (e.g. Chess and Backgammon), the best letter game readily available was Anagrams. Around that time, he was reading "The Gold Bug" by Edgar Allan Poe and noticed a line containing the English letter distribution. This gave him an epiphany: Anagrams would be more fun if the most common letters in English were more common in the game. He carefully analyzed letter frequencies in newspapers and other printed works to determine the ideal letter distribution for the game. With a few other changes, he named his project "Lexiko". The game design was rejected by games manufacturers such as Parker Brothers and Milton Bradley, but Butts was able to sell copies on his own, though not enough to recoup his development expenses. In 1938, he began work on a board game based on "Lexiko", which he called "Criss-Cross Words", which was eventually renamed "Scrabble".