Most point and shoot cameras come with built in lens caps that will automatically snap shut when the camera gets powered down. Larger ones however don't. And you'll need to manually put the lens cap back on. X-Cap, is a product that attaches to a camera lens like a removable cap. It features an opening that automatically opens and closes when the lens is extended or retracted.
The cap is designed to work for cameras where the lens doesn't fully retract into the camera's body. X-Cap should work for everything from Micro Four Thirds snappers to full sized DSLRs. The cap has a trigger on the backside which the camera makes contact with when the lens gets retracted which means it never has to be removed. Check out the video of it below: [Engadget Chinese via Engadget]