Just what you've always needed -- a dodecahedron shelled from inside by an icosahedron. A Platonic solids mishmash perfect for catalyzing conversation or maybe using as a shadow-producing shelf ornament. Ours is not to reason why....

Also included is the symmetrically aligned perforation of the dodecahedron by its oversized dual icosahedron. Not as interesting in my opinion, but useful for discussing the concept of the duals of Platonic solids. Just be sure to point out that the actual dual would not perforate the shell -- the icosa vertices would just touch the centers of the dodeca faces.

Finally, I've included the solids that I used to generate these mashups.