Sean Ragan created this fantastic dodecahedron speaker, which not only looks good, but also has some interesting acoustic properties:
At normal listening distances, an array of twelve speakers arranged on the faces of a dodecahedron is a very good approximation of a point sound source, and the sound waves it produces are very close to perfectly spherical. A dodecahedron speaker can be a useful tool in acoustics research, and is definitely a fun toy to pull out at parties. They are available commercially, but very expensive. Some people build their own, but the odd compound angles and the high degree of accuracy and precision required in the parts make for challenging work with manual tools. But it’s easy for a 3D printer.
If you have your own 3D printer to make some of the components, this beautiful speaker can be built for just under $100 in parts and materials. Sean wrote a full guide to building it and he even shared all of the design files on Thingiverse.