"Arab Spring" is the term used to refer to a number of movements for more democratic rule in Arab countries. Prior to the Arab Spring, there had been very little true democracy anywhere in the Arab world. Instead, governments (whether monarchies or otherwise) were authoritarian. During this movement for democratization, authoritarian governments have fallen in Tunisia, Egypt, and Libya.
The movements have tended to take the form of protests against corruption in the governments and against their tendency to suppress the rights of the people. The protests started, for example, in Tunisia with a man burning himself to death because of corrupt treatment at the hands of government. In Egypt, protests centered around the fact that the government suppressed people's political rights.
The Arab Spring has not yet been successful in countries other than those mentioned above. In places where it has overthrown governments, it is not yet clear whether the new governments will be truly democratic.
The Arab Spring was the popular revolutionary uprisings in Arab countries, more specifically in the Middle East and in northern Africa. It had begun in Tunisia in December of 2010 and took hold in Egypt, Libya, Syria, Yemen, Bahrain, Saudi Arabia, and Jordan. The reason for the conflict was about protestors challenging the existing authoritarian government at the time. This was also called the Jasmine Revolution.