iKnowthat.com has multimedia educational games for kids ages 2-12.

Operation Optics Game

In this interactive arcade style game, kids learn about the basic science of light and  the properties of lenses, mirrors, and prisms.

The goal of this game is to protect Earth from invading robotic ants. In one level, kids use a laser and a mirror.  In another level, kids use a convex lens to focus light.  In a third level, a concave lens is used to diffuse light beams, while in the forth level a prism is used to produce a color spectrum.