If it extrudes, it prints.
The recently released Imagine 3D printer from Essential Dynamics can 3D print in just about any material that can be extruded at room temperature. In fact, it can print two different materials at the same time. This is made possible by the unusual use of syringes to dispense material.
Food printing is probably the most obvious application (and the system is food-safe), but the Imagine could also be used to make objects with unusual combinations of other materials. The Imagine is currently for sale ready to use for $2,995 plus $299 S/H.