Thats right, this homemade 3D printer is made of Lego, and you could make one as well! The NXT controls the LEGObot’s power elements: a hot glue gun, a fan and an old VHS camera motor, which powers the printer’s extruder and build platform. So it actually uses melted glue as the material of choice. Besides that It is only made of Lego Parts, and while no match for a MakerBot or similar commercial 3D Printer, It certainly is cool!
Here is the instructables link