Here’s an interesting board for the Pi. It allows you to connect two cameras (or 4 if you stack two boards) to the Pi and then switch between them. I can imagine this being used for security camera applications where you want to have camera facing in multiple different directions. I can also imagine some kind of rig taking pictures very rapidly by switching between the cams. I suppose you could even do some kind of rudimentary 3D with it by very rapid switching, but obviously there would be a little flicker. Read more on the IndieGoGo page.

Here’s a video of the board working with 4 cameras: