From an article in yesterday's New York Times about the University of Chicago economics department.
"Casey Mulligan, who got his B.A. at Harvard and took his doctorate at Chicago, turned down offers from Harvard and Stanford to stay at Chicago, says: `When I come into my office on Sundays, Gary Becker is in his office, too. If I went into Littauer on a weekday, I wouldn't be able to find Larry Summers.' Professor Summers, arguably Harvard's biggest star and winner of this year's John Bates Clark Medal, left his research post (and his office in Harvard's Littauer building) to become first chief economist at the World Bank and now Under Secretary for International Affairs in the Clinton Treasury."