How about George Clooney in The American? He played an assassin who took a job to build a weapon with the firepower of a submachinegun and the range of a rifle. Scenes of snipers carrying a case with a brokedown weapon in it are fairly common in movies and TV. But there are never more than five or six parts to be assembled...snap, click, and it's done. Clooney's character ordered the various things he needed, and then he put it all together...nuts, screws, trigger guard, everything. There must have been close to a hundred pieces, but Clooney never hesitated, never picked up the wrong part. And he did it in one continuous take. THAT was impressive.