Henry Minsky, Marvin's son, works at Nest on the "Thermogotchi", a digital pet that lives on your wall, that's a sensor-driven, Wi-Fi-enabled, self-learning, programmable thermostat which you train to adapt to your habits and lifestyle, and keep happy by feeding love and energy.
Google liked the idea so much that they acquired the company that developed it. So if that isn't a practical application of AI, I don't know what is.