It is clear why Mr. Wilson was at this event, but why would Valerie Plame be there?
We now know that Ms. Plame had been a covert agent, her appearance at this function would have had to be cleared with her superiors. Why would she be there if not on official business?
I've been wondering the same thing, and haven't come up with an answer yet. Was Plame working on Counterproliferation yet at that time? This would've been early 1997, and would've been about the time the CIA recalled her from overseas assignments, reportedly due to concerns over Aldrich Ames.
PS to add on a thought I just had: maybe she was there in her capacity as an "energy analyst" for Brewster-Jennings, i.e., to make contact with people at the Turkish embassy who might be of interest to the CIA.