Rush Hour is a sliding block puzzle on a 6x6 grid, where the tiles represent cars.
Rush Hour is a sliding block puzzle invented by Nob Yoshigahara in the 1970s. It is played on a 6x6 grid with 14 sliding blocks. The sliding blocks represent 12 cars (2 squares) and 4 trucks (3 squares), each colored differently.
Cars and trucks can only be moved within a straight line along the grid, but cannot be rotated. The goal of the game is to get the red car out of a six-by-six grid full of automobiles by moving the other vehicles out of its way. However, the cars and trucks (set up before play according to a puzzle card) obstruct the path which makes the puzzle harder.
See also this Wikipedia article.