I think I wrote this a while ago, so I have no idea about the quality...
What can one do when one discovers that life is pointless? The basic responses are probably some form of misery and despair, often accompanied by a certain self-destructiveness, or an attempt to find some reason that it is okay to live despite the fact that life is ultimately pointless.
The argument that life is pointless is pretty easy to figure out. We live, often poorly, and then we die an ignoble death. We all shit, piss, cough, hiccup, and generally are not capable of anything incredible. Even if one is incredible and decides that their remedy to life's pointlessness is to leave some legacy or to accomplish something, very few will understand their accomplishments well, and many not at all.
Despair is an appropriate response to this, and so is suicide. An inappropriate response is religion, which serves only to fool men and give them a false sense of purpose. Purpose?! Stripping oneself of sensibilities and living life telling others to do the same is purpose? Not at all.
Despite saying all this, I do not think that any of those are appropriate responses. There are so many ways that one can find pleasure in life that it utterly exceeds that which brings us displeasure, at least when are minds and bodies are fit and sound. I think that the proper response is thus to throw oneself into that pleasure in the most selfish, wholehearted way possible, whether it is just a way to "waste time," whether it is a pursuit, or anything that it may be.