Lordy lawks, this is the best thing my eyes have ever seen:
It's a free mod for Unreal Tournamnt 3, and can be downloaded here.
The mod's creator, LordSimeon, describes it as,
"More of a test at playing around with the new Physics options, so almost the whole map is destructable. There's 20 or so various types of LEGO blocks built into houses, walls and shapes. By the end of the match, it's mayhem. There's a lot I could have done, but it is mainly a physics test."
LEGO are notoriously protective of their IP, so, er, download this one before they notice.