Most of us don't have access to personal fabs yet, so in the interim you must use services. The good news is that there are several available. One interesting service is Fabjectory, which uses 3D Printing technology to produce real artifacts from virtual designs. That means you can send them your SketchUp designs and have the object produced and sent to you. Fabjectory also can produce real objects from your Nintendo Mii or your Second Life avatar. In fact they will accept any 3D object created in Second Life for printing – as long as it is structurally feasible (e.g. Components have minimum width, etc.) Costs range from $50-200 depending on complexity, and delivery takes up to five weeks (since I suspect Fabjectory is using down time on a commercial 3D printer).