RepRap is a free desktop 3D printer capable of printing plastic objects. Since many parts of RepRap are made from plastic and RepRap can print those parts, RepRap is a self-replicating machine - one that anyone can build given time and materials. It also means that - if you’ve got a RepRap - you can print lots of useful stuff, and you can print another RepRap for a friend

Przemek Jaworski form Projektowanie Parametryczne showed RepRap 3D printer during parametric design workshop. It works excellent as for home made 3D printer!