Backgammon
Backgammon is one of the oldest known board games. Its history can be traced back nearly 5,000 years to archeological discoveries in the Middle East, originally in Iran. It is a two player game where each player has fifteen pieces ("checkers") which move between twenty-four triangles ("points") according to the roll of two dice. The objective of the game is to be first to "bear off", i.e. move all fifteen checkers off the board. Backgammon is a member of the tables family, one of the oldest classes of board games.
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".