Rules: Send your guess in the subject of an email to firstname.lastname@example.org. Include your name and email in the body of the message. One guess per person. All guesses must be sent by Saturday noon CDT. Closest guess to the attendance announced at the business meeting Sunday night will receive an invitation to open a Gmail account (still in Beta testing). In case of tie, first closest guess received will win. Anyone involved in STOC organization is ineligible. Not responsible for delayed or undelivered email. My decision of the winner is final. Contest not sponsored or affiliated with Google or ACM SIGACT.
Results Update 6/14: Total paid attendance was 242. The closest at 254 was Nanda Raghunathan, second place at 223 was Kamalika Chaudhuri and third at 265 was Chandra Chekuri. We have some extra invites so we've decided to give gmail accounts to all three. Congratulations and thanks to everyone who participated.