The sorrow and the pity: Diane Keaton's May 2010 SMU appearance is, alas, already sold out.I was just on the SMU Web site and noticed that yesterday, the university announced the complete roster for the 2009-10 Willis M. Tate Distinguished Lecture Series, which tends to sell out fast -- as evidenced by the fact that the first installment (featuring Pultizer winner Thomas Friedman, CNN's Fareed Zakaria and moderator David Gergen) and the last one (Diane Keaton) are already, well, sold out. But ti