Here's a short-and-sweet example from our friends at the Idaho Fire Sprinkler Coalition on the rapid response of home fire sprinklers.
Earlier this year, a resident discarded smoking materials in a small, plastic trashcan in her garage. A fire spread from the trashcan to a nearby upholstered chair, eventually activating a sprinkler head. (Sprinklers in accordance to NFPA 13D, Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes, are not required in garages. The resident's jurisdiction, however, requires sprinklers in these areas when an occupied living area is above the garage.)
The sprinkler head completely extinguished the fire. There was minimal damage to the garage, no damage to the adjacent living area, and the garage was dried out in two hours.
Looking for other examples of sprinkler saves from across North America? Check out the Sprinkler Saves website.