So, what exactly is Warhammer 40,000?
In a nutshell, each player collects an army of Citadel miniatures then, using the Warhammer 40,000 rulebook as a guideline, they fight epic battles against their fellow generals. Dice (like you'd find in almost any board game) are used to determine success and failure: to decide whether a bolter shell hits its target, or whether a lascannon blasts through the armour of a tank. Each game is played, not on a regular 'board' but on a special gaming area where models are not confined to 'squares' but are free to move as their controller wishes. Because Warhammer 40,000 is not played on a set game board, tape measures or rulers are used to see how far a miniature can move - an agile Eldar jetbike can travel faster than a foot-slogging Imperial Guardsman after all.
That all might sound a little complicated, but most Warhammer 40,000 players find that after just a short game or two they've grasped the basics. Seasoned Warhammer 40,000 generals find that the rules become second nature, and they seldom need to refer to the rulebook at all.