LucasArts http://www.lucasarts.com/ is the computer gaming branch of George Lucas' business ventures.
They are known for some amazing games such as ManiacMansion?, Day Of The Tentacle, the Monkey Island series, the Indiana Jones series and more. Very notable is their SCUMM adventure game engine, widely considered to be a masterpiece.
[The mentioned games are graphic adventure games. Someone feel free to elaborate on LucasArts' other game types, of which there are many.]