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Thomas Merton Center Calendar Calendar of Peace & Social Justice Events is published in their free monthly, the New People, and online: http://www.thomasmertoncenter.org/calendar/
Independent Media Events Calendar http://indypgh.org/calendar/
University Lectures – Most on-campus events are free and open to the public at-large. Some of the bigger speakers will be listed in the City Paper and the Post-Gazette and promoted on posters around the city, but the smaller lectures are usually advertised by email. There are a million list-serves for all the lectures and seminars out there. My advice is to contact the assistants in the department that interest you, and ask them to add you to their announcements list.
Here are some we know about:
Carnegie Mellon University: http://my.cmu.edu/site/events/
University Lecture Series – held in the Adamson Wing of Baker Hall
AB Political Speakers – this year they brought John Waters and Inga Muscio to the campus, among others. http://activitiesboard.org/lectures.php firstname.lastname@example.org Phone 412.268.2105
Carnegie Library Check the bulletin boards at your local branch or check ‘em all online: http://www.clpgh.org/dontmiss/