AIESEC is a French acronym. It stands for "Association internationale des étudiants en sciences économiques et commerciales" or in English, "International Economic and Commercial Sciences Students Association". It is the world's largest student run organization and provides you with a platform to go on an international internship or become a leader with global perspective.
From what I gather, there are over 60'000 members in over 2100 universities/colleges in over 110 countries over the world. There is a chapter here at McMaster and they have about 35 members. They are always looking for more people to join and develop themselves.
If you are looking for an opportunity to develop yourself as a leader, as a professional or as a person, to expand your personal/professional network or to experience an internship abroad, all the while learning what it's like to be globally and socially conscious... join AIESEC.