Not an april fool joke. In this kind of 3D there are two images which are polarized in a different way. 3D glasses use polarization to show to each eye only one image. If you look a 3D film without glasses, both eyes are going to see both images, that's not to be comfy. This glass has the same polarization for both eyes, so you can see a 3D in 2D, both eyes see only one (the same) image of the two which are projected.

This presupposes you have money to waste and you really like your friends. Otherwise you could just go to a conventional movie screen. Some people would feel "asocial" if they singled themselves out going to a different projection room, or a different cinema. The solution is simple but brilliant