Sony has recently published patents which will allow two-player 3D gaming on a single screen. The new technology could spell an end to split-screen gaming, but is unlikely to see the light of day for a few years at least. Sony's method would allow player one to see frames one and three whilst player two would see frames two and four. Current technology requires a display with a 120 Hz refresh rate so it seems likely that we'll have to wait for 240Hz screen technology to become commonplace before two-player 3D becomes a reality. PDFs versions of the two patents are available.