What is a paradox? More importantly, what is infinity? These concepts can blow one's mind in the best way possible and they are the subject of this course at MIT. Offered up as part of that august institution's Open CourseWare initiative, this semester long course was first offered in spring 2013 by Professor Agustin Rayo. In short, the course "explores different kinds of infinity; the paradoxes of set theory; the reduction of arithmetic to logic…." On the site, visitors can download the syllabus, the course calendar, the readings, and look over the lecture slides. The Readings area contains some lovely pieces, including "The Paradoxes of Time Travel" and "The Eleatic Hangover Cure."