Mobile and location-based serious games can provide learning experiences anywhere and anytime by personalizing to a user's schedule and context. Various technologies like GPS, WiFi, cameras, and sensors can be leveraged in mobile devices to go beyond just phones. Some examples of early location-based serious games include reverse geocache puzzle boxes, Mogi for collecting virtual objects in real locations, and Shadow Cities for augmented reality territorial control. However, challenges remain in terms of technology limitations, user privacy concerns, and ensuring interoperability across platforms. A bottom-up approach starting with small-scale experiments is recommended to help address these challenges.