There are several FR threads, but here is a news link:
Author booed for Bush criticismGulf Daily News, Bahrain - May 26, 2004NEW YORK: Author EL Doctorow, who penned Ragtime and City of God, was stunned when his commencement address at a Hofstra University was booed by some students ...
There was another boo-ing this past week (of a prominent lib/dem) for anti-Bush remarks, but I can't recall who it was or where.