Last February at the Casino, Chicago's elegant private club tucked behind the John Hancock Center, an exceptionally festive party brought together Chicago's A listers. The occasion was a birthday celebration for Neal Zucker, civic philanthropist and chief executive of Corporate Cleaning Services, a window-washing company. Guests included Mayor Richard M. Daley; M. K. and J. B. Pritzker; the investment management executive Joan Steel; Trish Rooney Alden, founder of a records management company; and Marko Iglendza, the airport concessions king. But the arrival of Desirée Rogers, then the White House social secretary, made the biggest splash with a crowd not easily stirred.