Here's a string theory you may be able to wrap your head around.
You locked your keys in your car, your dog swallowed them, they fell in a sewer grate or they're all the way in the house and you're tired... I don't know your life. But whatever the case, in the event that your keys aren't handily available, all you need is a string and some basic knot-tying skills and voila — open sesame.
Tie a knot, slide the string through the car door and shimmy the knot down to the car door lock.
Gently lower your knot down. Gentle... gentle... gentle... got it.
This is not a how-to guide to break into someone else's vehicle. Use your string powers for good.