The most recent project from the Harper & Gygi labs, BioPlex 2.0 (Biophysical Interactions of ORFeome-derived complexes), was featured in Nature and uses affinity purification-mass spectrometry to elucidate protein interaction networks and co-complexes nucleated by more than 25% of protein-coding genes from the human genome. It is currently the largest such network assembled, consisting of 56,000 candidate interactions and more than 29,000 previously unknown co-associations.  You can read further about this project here.