I believe that Silicone rubber has been an overlooked material with a lot of potential for a long time. I would be surprised if I was the first person to think of using it in sculpture, but I'm sure I wasn't the only kid to tickle that sample dab of silicone they used to stick on the display cards and wonder what else it might be good for.
It can be used to make biological and architectural models, art and craft projects, jewelry and other things. Since it also has survival value for things like stopping leaks, and repairing things at home, it is a good material to become familiar with.
Step 1: Tools
100% RTV silicone rubber comes in a few basic colors, such as clear, white, black, bronze, and aluminum. You can make your own colors by mixing powdered pigments with clear silicone. Mix the ingredients on a palette with a palette knife. Transfer silicone to plastic tipped hypodermic syringes (pet store) for precise extrusions and fine details. Dick Blick Art Supplies is a good place to get fancy colors online: http://www.dickblick.com/search/?q=powder+pigments&x=26&y=9&sp_cs=UTF-8 Cheaper pigments by the pound can be found in hardware stores. They are normally used for colorizing cement.
You can build forms up like a clay coil pot, extruding lines upon lines to build up walls of silicone. Work on a wire armature to build figurines, etc. Spread it on a non-stick flat surface to make sheets of the material. Polyethylene plastic makes a good non-stick surface. I have a polyethylene plastic kitchen cutting board that is my favorite work surface.
Save your empty cartridges, clean them out, and use them for other things, such as maracas, or for artist's acrylic paint dispensers.