An incredibly smart and potentially time-saving tip from Ian Lesnet at Dangerous Prototypes. He writes,
Search Github hardware by component to find examples and references for your next project. Big schematic and PCB previews mean quick and easy browsing without opening a CAD program.
There are a number of limitations. Only Eagle projects are indexed, a search for KiCad files inspired little interest in expanding. Before Eagle 6.0 files were not XML and will not be included. Github search only indexes code files up to ~390K, larger files will not be included. If Github improves access via the API we will expand the index.