A few online resources for teaching multimedia applications and concepts:


Site Description
Kid Pix 3D - quick and easy online animation creation
Fluxtime - online or downloadable animation creation studio
GoAnimate - Make Professional Animated Videos
Scratch - animation programming site from MIT
HUE Animation Studio  
MonkeyJam  a digital penciltest and stopmotion animation program. It is designed to let you capture images from a webcam, camcorder, or scanner and assemble them as separate frames of an animation.
Blender - 3D modeling and animation creation software
Unity3D a game development ecosystem: a powerful rendering engine fully integrated with a complete set of intuitive tools and rapid workflows to create interactive 3D and 2D content; easy multiplatform publishing; thousands of quality, ready-made assets in the Asset Store and a knowledge-sharing community.