Kimiko Ryokai from the MIT Media Laboratory developed an interesting interactive brush for kids to explore the environment.

From the I/O Brush Project page:
"The I/O Brush is a drawing tool to explore colors, textures, and movements found in everyday materials by 'picking up' and drawing with them. I/O Brush looks like a regular physical paintbrush but has a small video camera with lights and touch sensors embedded inside. Outside of the drawing canvas, the brush can pick up color, texture, and movement of a brushed surface." This a pretty cool idea.
More details and videos about the I/O Brush site and on BBC News.