The Megalith Game is a LEGO Challenge, allowing two people to face off in a game of defense and offense. One person builds a building and another person builds a device called a Megalith. Then, two marks are made on the ground. The building is placed on a line and the person who built the Megalith starts at the other line. The Megalith-builder would throw their Megalith at the building, with the goal of causing as much damage as possible. The number of hits required to destroy the building is recorded. If the building destroys the Megalith before it is destroyed, then the defender win. No repairs are allowed between strikes.
There are many obvious building designs that would withstand a Megalith - a solid block of bricks would not sustain damage from a Megalith, but it is generally banned because it is a trivial design. The far more interesting challenge is to maximize interior volume while maintaining enough strength to survive hits. Lessons learned from the Megalith game have advanced the art of Impact resistant buildings.
One of the finest Megaliths ever created was based on the hull of the LEGO Rescue Ship. Since its front is pointed, it was capable of destroying every building it ever faced, until it ran into the cube.