You know the drill: campfire, toasted marshmallow, chocolate chunk and graham cracker. Put them together and you've got a childhood favorite rooted in nostalgia and emotion.

The S'more. It's everything come summer - and OREO knows it.

On May 22, the cookie maker launches the limited-edition S'mores OREO. Featuring the first-ever graham flavored cookie and layers of chocolate and marshmallow-flavored creme, the cookie is an easy substitution for the real thing. (Though honestly, we miss the charred taste of campfire marshmallows: come on, you know they ALWAYS catch on fire!)

To help promote the new cookie, OREO and Zipcar have teamed up. Reserve a car before May 21 for Memorial Day Weekend and you may just find cookies in your rental. Sweet!