Penn Jilette addressed the Reason Rally via video (I'd heard he attended the first day, but I may have been mistaken). There's not much substance to his address, but it's good for a cheer:
More substance is to be found in the speech of Nate Phelps – the estranged son of the notorious Fred Phelps of the Westboro Baptist Church (who were a short ways away, protesting the Rally). He hasn't updated his blog since July of last year, but there's some good stuff on there as well.
I absolutely love this line from his speech, which echos Sam Harris' thesis in The End of Faith: "If you invoke faith as justification for your belief, you must accept the same from others. And every person who retreats to faith bears a responsibility for every act of hate and violence justified by it".