It appears they didn't like what conservative columnist Ann Coulter had to say.
Two men ran on stage and threw custard pies at Coulter as she was giving a speech at the University of Arizona last night. Coulter was hit in the shoulder. The men were arrested by university police.
In her speech, Coulter trashed Democratic presidential candidate John Kerry, liberals and Democrats, while praising conservative students who attended her speech.
You can view the incident here.