Shooting from two directions at the same time makes for some interesting photography
Usually, concept cameras are interesting ideas that'll never work in reality as they have no basis in how a camera actually works. But the DUO Binary Camera concept by Chin-Wei Liao is not only a cool concept, but one that's actually functional, with fully working prototypes.
The DUO is a pair of cameras that click together with strong magnets, each one pointing in an opposite direction. You and your subject both have to hold the shutter release to fire it off, snapping a portrait (or more probably a selfie) of the both of you.
Liao created the DUO for RCA's Innovation Design Engineering program, and describes it as "By being both photographer and subject at the same time, it enables people to have fun documenting and being documented." So it would do away with one person always being excluded while taking a photograph.
Since this is just a concept camera, it won't be coming to stores at any point in the too near future. But for something remarkably similar, there's Dblcam, which does the same thing using both cameras on your iPhone.