Elissa Lerner: If holiday cheer is starting too soon for you this season, join the club. The Humanist/Atheist/Secular/Nontheistic club, that is. Tuesday marked the launch of the "biggest atheist ad campaign in history". This holiday season, atheists are hoping to break into the market share as well. For those who are still going through the motions, the ads present an option to "celebrate reason." But is this atheist campaign guilty of the same sin of over-simplification ascribed to so-called "Christian America"? After all, even Sam Harris believes in God (or "God") these days. If only billboards had some fine print...