Rubik's Cube is a 3-D combination puzzle invented in 1974 by Hungarian sculptor and professor of architecture Ernő Rubik and originally called the Magic Cube. The puzzle won the German Game of the Year special award for Best Puzzle that year. As of January 2009, 350 million cubes had been sold worldwide making it the world's top-selling puzzle game. It is widely considered to be the world's best-selling toy.
This is a classic 3 x 3 cube (81mm x 81mm x 81mm), and as with all others the idea is to twist the various faces to get all sides to be a single colour. Not as simple as it appears.