How does a player score 15 during the play stage of cribbage?

During the play stage of cribbage, a player scores two points by playing a card that brings the running total of the cards played to exactly 15.1

As players take turns laying cards faceup and announcing the new total, the player whose card causes the sum to reach 15 is awarded these points immediately. This is one of several combinations—along with pairs, runs, and the "go"—that can be pegged during the play stage before the final showing of the hands.1