The LIVE COMPONENTS blog is a fantastic resource for parametric designers for both inspiration and technical knowledge. It is run by Hyoung-gul Kook, a specialist in Advanced Architectural Geometry from Columbia University and an architect at Weiss/Manfredi in New York. The blog details a wide range of projects which are mostly based in Grasshopper, and provides detailed tutorials of how their definitions work. This forces you to build the definitions yourself and understand more fully the process being followed, as opposed to downloading a ready made Grasshopper file. Projects range from complete systems such as La Fabrique Sonore to individual components.