From the Center For Inquiry:
International Blasphemy Rights Day takes place every September 30th, to commemorate the publishing of the Jyllands-Posten Muhammad cartoons. The purpose of this event is to set a particular day as a day to support free speech, support the right to criticize and satirize religion, and to oppose any resolutions or laws, binding or otherwise, that discourage or inhibit free speech of any kind. The focus on ‘blasphemy’ is simply because it is such a salient issue, and one for which a lot of consciousness-raising is necessary.
The goal is not out to promote hate or violence [emphasis added]. While many perceive blasphemy as insulting and offensive, it isn’t about getting enjoyment out of ridiculing and insulting others. The day was created as a reaction against those who would seek to take away the right to satirize and criticize a particular set of beliefs given a privileged status over other beliefs. Criticism and dissent towards opposing views is the only way in which any nation with any modicum of freedom can exist.