Theater of the Absurd refers to a series of that focused on a particular philosophy. The philosophy came out of Albert Camus' essay "The Myth of Sisyphus", which postulated that all the energy man spends searching for meaning is life is useless. So much of literature searched for meaning in man's life and man's struggles, and postulated on what that meaning was - the absurdists latched onto Camus' idea and created literature that highlighted the absurd in man's actions and rationalizations. These plays used humor, slapstick comedy, wordplay, and other devices to achieve their purpose.
"Waiting for Godot" does fit into this category. Samuel Beckett is considered a premier absurdist, and this is his most well-known play. The characters of "Godot" - all 5 - are ridiculous in their behavior. Vladimir and Estragon rely on the assurances of a young boy in determining their daily work - waiting. These two men wait, apparently homeless, because a young boy promises them that "Godot" will appear the next day. Instead of trying to move forward with their life and get out of their situation, they sit around in meaningless hope that the next day will bring them this mythic Godot. They even contemplate committing suicide, having seen how meaningless their days are, but don't follow through - not because they have a will to live, but simply because they can't be bothered.
Why are we here, that is the question. And we are blessed in this, that we happen to know the answer. Yes, in this immense confusion one thing alone is clear. We are waiting for Godot to come.
In the above quote, we can see the meaningless of their actions. They are waiting for Godot - who obviously won't arrive.
Part of what makes the absurdist theatre so thought provoking and so powerful is that is arises from a world of disorder and of chaos, and seeks to bring light to this. The absurdist authors write in the wake of 20th century notions of "progress" and "civilization." After seeing wars in which millions were killed and human cruelty at an unprecedented level, there is little, if any, moral or ethical order present. The absurdist writers comment, critique, and raise this and ask how we, as the legacy carriers for the future, will change this state of affairs. Beckett's ideas of paralysis and inaction is evidence of this. The tramps keep on waiting for Godot. They keep on waiting and we, as audience members and readers, raise our hands in disgust and repugnance criticize them for their inaction. Yet, as Beckett said, "It's all about symbiosis." What patterns of "tramp" behavior do we possess? Are we creatures of wait? Of paralysis? The absurd theatre might not be about the plays, but really about us. That's what makes it so powerful.