Now. Existentialism is, essentially, the contemplation of existence. Often the parable of Sisyphus is used as the existentialist mascot. The futile image that the parable creates is to symbolize our life...for, linking with post-modern strains of thought (which, remember, seek to re-evaluate all we have previously assumed to gain a higher truth), there is technically nothing more than this struggle. However, existentialism largely wished for us to accept this. Don't hate the struggle...it is ALL you have to depend upon. Your language, your concept of time, your concept of relationship, your concept of government, your concept of organization, your concepts of religion...all will fail you. However, the boulder will not. Accept and love the boulder.
Therefore, Existentialist Agnosticism combines these two views. We have no proof there is god. So, for your own sakes, stop worrying about him and live your life.
I feel that we all could learn from existentialist agnosticism.