The movies use very fast alternating polarised frames and you have circular polarized glasses on that allow each eye to only see the correct image...something I can't see TV's being capable of in the near future.
"RealD 3D cinema technology uses circularly polarized light to produce stereoscopic images. Circular polarization is preferable to linear polarization because viewers are able to tilt their head and look about the theater naturally with no loss of 3D perception. Linear polarization, on the other hand, requires viewers to keep their head within a certain degree of tilt for effective 3D perception, otherwise they can see double or darkened images.
The projector alternately projects the right-eye frame and left-eye frame 144 times per second, and circularly polarizes these frames, clockwise for the right eye and counterclockwise for the left eye. A push-pull electro-optical modulator called a ZScreen is placed immediately in front of the projector lens to switch polarization. The audience wears recyclable circularly polarized glasses to make sure each eye sees only "its own" picture, even if the head is tilted. In RealD Cinema, each frame is projected three times to reduce flicker, a system called triple flash. The source video is usually only (2x)24 frames per second (which can result in a subtle ghosting and stuttering on horizontal camera movements). A silver screen is used to keep the light polarized and to reflect back as much light as possible to counter polarization losses. The result is a 3D picture that seems to extend behind and in front of the screen itself."