Corrected on 10/4/07: An earlier version of this article incorrectly stated that the University of California-Davis had rescinded a speaking invitation to former Harvard President Lawrence Summers; it was the Board of Regents of the University of California who invited Summers to speak at a board meeting in Sacramento and later rescinded the invitation.
Sept. 24, 2007
Iranian President Mahmoud Ahmadinejad speaks at Columbia University while hundreds of students protest around the campus. Among his comments: "In Iran, we don't have homosexuals, like in your country."
Sept. 14, 2007
The University of California Board of Regents rescinds an invitation to former Harvard President Lawrence Summers after 300 people sign a petition opposing the visit because “inviting a keynote speaker who has come to symbolize gender and racial prejudice in academia conveys the wrong message to the university community and to the people of California."
Nov. 30, 2006
A fire alarm is pulled twice, students are assaulted, and protesters boo during a speech by Rep. Tom Tancredo, an outspoken opponent of illegal immigration, at the Michigan State University College of Law.
Oct. 4, 2006
Angry students storm the stage, overturn tables, and unfurl a banner in Arabic and English reading "No one is illegal" at a lecture by Jim Gilchrist, founder of the Minuteman Project border patrol group, at Columbia University.
Sept. 10, 2006
As former Iranian President Mohammad Khatami arrives for a speech at Harvard University's Kennedy School of Government, he is met by approximately 200 protesters angrily asking him to stand up for human rights. Khatami is blamed for failing to stop government crackdowns on student activists in Tehran.
April 27, 2006
President Hu Jintao of China speaks at Yale University as hundreds of protesters gather to criticize China's human-rights record.
Dec. 7, 2005
Conservative columnist Ann Coulter cuts short her speech at the University of Connecticut after being drowned out by jeers.
Feb. 1, 2005
Hamilton College in upstate New York cancels a lecture by University of Colorado Prof. Ward Churchill after threats of violence, thousands of negative E-mails, hundreds of newspaper articles, and hours of talk-show ranting. Churchill had sparked the controversy in an essay in which he compared the victims of the attack on the World Trade Center to "little Eichmanns."
Oct. 21, 2004
Ann Coulter's speech at the University of Arizona is marred by a pie-throwing incident. The pie misses her face and glances off her shoulder.
Oct. 12, 2004
Filmmaker Michael Moore battles hecklers chanting "four more years" throughout his "Slacker Uprising" speech at the University of Arizona, where he urges students to vote for John Kerry.
Nov. 7, 2003
At a lecture at Yale University given by Middle East scholar Daniel Pipes, about 50 students wear black gags over their mouths to protest what they view as his broad attack on Islam.