Twilight Struggle
"Twilight Struggle" was the highest-ranked game on BoardGameGeek from December 2010 to January 2016. As of August 2018, the board game occupies a fifth spot. Being released in 2005 it is the oldest board game in the overall top 10 ranking.
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".