The New Yorker has a piece on Jeff Dean and Sanjay Ghemawat, who are directly responsible for a many of Google's technical innovations. They have a very close collaboration and friendship that has spanned two different companies and a number of projects.
It's a great article about an extroardinarily deep and productive relationship. Towards the end the article whistfuly notes that they only spend a day a week coding together. The remarkable thing for me is that they spend a day together at all - Jeff leads a significant number of people, and Sanjay is a sort of uber-tech lead. It's rare to find senior folks able to regularly get in to the details in that way, even one day a week.