[Also posted at atheism analyzed].
Atheists are de facto Materialists. Materialism is a necessary consequence of denying the supernatural. As Materialists they tend to revere empiricism as a source of truth. And they are convicted of their own possession of the singular truth of the universe, that there is no first cause.
Since Atheists have possession of the truth, they should not be adverse to sharing it here with us. The truth, of course, would be material and in the form of empirical experimental data, replicated by separate disinterested scientific teams, unfalsified, yet falsifiable, peer reviewed and published in a major scientific journal. These are criteria frequently cited by Atheists, and should be agreeable to them.
Here is a partial list items requiring material, empirical proof (See Rules below):
Note: If you can prove #4 (abiogenesis), there is $1,000,000.00 waiting for you here.