• NASA's Jet Propulsion Laboratory's (JPL) Mars Rover [Web Link]: An immersive, interactive demo of a Mars rover mission, with beautiful graphics and realistic simulations.
• Google's Tilt Brush [Web Link]: A VR painting demo that lets you explore and manipulate 3D art in space.
• The Amazing Mazes of Kono [Web Link]: An addictive, puzzle-filled demo that uses WebGL and physics simulations.

Map-based demos:

• Google Earth's Voyager [Web Link]: An interactive globe that takes you on a journey through stunning, high-resolution imagery and augmented reality experiences.
• ArcGIS Online's Story Map [Web Link]: A web-based mapping platform that allows you to create interactive, multimedia stories and apps.
• Mapbox's GL JS [Web Link]: A powerful, open-source mapping library that enables you to create custom, dynamic maps for any project.

Gaming demos:

• Unreal Engine's Master Chief Collection [Web Link]: A showcase of the Unreal Engine 4's capabilities, featuring gameplay from various Gears of War and Halo games.
• Valve's Portal 2 [Web Link]: A beautifully rendered, interactive demo that showcases the Source game engine's capabilities.
• Unity's Robot Rush [Web Link]: A fast-paced, interactive demo that highlights Unity's 3D game development features.

Other notable mentions:

• OpenCube's BrainHQ [Web Link]: An interactive, neuro-plasticity-based cognitive training demo.
• IBM's Watson's Jeopardy! [Web Link]: A demo that showcases the power of artificial intelligence, featuring Watson's performance on the popular TV game show.
• Microsoft's HoloLens [Web Link]: A demo that showcases the potential of augmented reality, featuring interactive holograms and spatial computing.