Beginning with Rouge Trader in 1987, Warhammer 40K has expanded into a game of epic scale combat. Set in the dark and depressing 41st millennium, 40K tells the story of the Imperium of Man and its constant war against aliens, mutants, demons, and heretics. Currently in its fifth edition, 40K has changed significantly since its first release, but it has always been an in depth game with complex rules.
Warhammer 40K can be played pretty much at any scale with only a few modifications. A typical tournament game will take a little over 2 hours to complete and features $300-$400 worth of models. Modeling and figure painting is an important aspect of this game.
Few will argue that Games Workshop shouldn't be added to the list of most successful game companies. They are most well known for their Warhammer 40K and Warhammer Fantasy lines, but they have produced numerous smaller games over their history. From their beginnings in 1975, Games Workshop has seen significant changes to its business model. First it made game boards and a little later it became a publisher of 3rd party content. Their next step was to found citadel miniatures and they entered the market of producing miniatures for role playing and tabletop games. During the 80's, the properties of Warhammer 40K and Warhammer Fantasy were born. In the 90's the company refocused on these core lines and started opening retail stores. As GW enters it's 35th year, it has expanded to be a household name for gamers and many non-gamers thanks to its popular video games.