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.
Dots and Boxes
Dots and Boxes is a pencil-and-paper game for two players (sometimes more). It was first published in the 19th century by Édouard Lucas, who called it la pipopipette. It has gone by many other names, including the game of dots, boxes, dot to dot grid, and pigs in a pen.
Starting with an empty grid of dots, two players take turns adding a single horizontal or vertical line between two "unjoined" adjacent dots. The player who completes the fourth side of a 1×1 box earns one point and takes another turn. (A point is typically recorded by placing a mark that identifies the player in the box, such as an initial.) The game ends when no more lines can be placed. The winner is the player with the most points. The board may be of any size. When short on time, a 2×2 board (a square of 9 dots) is good for beginners. A 5×5 is good for experts.