Here's an interesting essay about the common elements that characterize most revolutions. Writing for the Atlantic Post, Dr. Haytham Mouzahem, a Middle East analyst for the newspaper, argues that while revolutions may have different catalysts, they share common elements that include "circumstances of time and place and diverse cultural, religious, social, political and economic communities that witness these revolutions."
My AP world students recently completed a project comparing the causes of the French Revolution with one of the countries involved in the Arab Spring. This might have been a great essay for them to read before starting because it offers some context about all revolutions.
Thanks to Joe Taraborrelli for tweeting the link.