Weirdest one for me: in "The Roads Must Roll" (1940) Heinlein invented the Segway. "A tumblebug does not give a man dignity, since it is about the size and sha

Weirdest one for me: in "The Roads Must Roll" (1940) Heinlein invented the Segway. "A tumblebug does not give a man dignity, since it is about the size and shape of a kitchen stool, gyro-stabilized on a single wheel. But it is perfectly adapted to patrolling the maze of machinery 'down inside', since it can go through an opening the width of a man's shoulders, is easily controlled and will stand patiently upright, waiting, should its rider dismount."