One of the things that makes me scratch my head when speaking with atheists, and the like (agnostics/apathetics/what have you) is that there is really no viable alternative to me than Christianity, at the end of the day logically speaking. This may read a lot like Pascal's Wager, for those of you familiar with it, but bear with me.
Basically, I understand that most forms of Christianity, from Orthodoxy, to Catholicism, Protestantism, and non-denominational-ism (?), etc, would agree that Christianity holds certain objective truth claims; that those who have faith in Jesus Christ of Nazareth will ultimately spend eternity with him and their heavenly father in the paradise of New Jerusalem, while those who ultimately reject him and rebel will join Lucifer/Satan/Leviathan to suffer ongoing punishment without end.
At the same time, in this current life, those who trust in Christ are promised a life of adventure and continuing wonder as we grow in our faith, though at the same time struggling against sin and darkness (an oversimplification, granted).
Now an opposing view, among many, is that there is no point in life; when we die, we die - there is nothing more, nothing less. While we live, we should aim to fecklessly seek to enjoy ourselves, or perhaps make a better world for our kids and grandkids, but let's face it - who really cares, because there is little point at the end of the day. We arrived here by random chance, and hence shall we exit.
That seems to be the stance of the staid atheist, at least traditionally. However, not many I know are quite of this ilk; they seem to have some faint new-age borrowed Buddhism going on, that there is some 'supernatural' akin to Kant's far-off noumenon - intangible but in theory possible.
Anyhow, there isn't really a counter Christian idea that there is something *else* we should be placing our trust in, or believing, a being whom, if we don't follow, we miss out on eternal reward, and are even punished.
Thus taking the major religions; what happens to Christians if Muslims are right, and Allah is the true creator of the universe, and Mohammed really was his prophet? How about if the Jews are correct and the messiah was not actually Christ, but has not yet come? And if the Zen Buddhists are right, and everything is nothingness, we must seek inner peace and enlightenment - attainment of nirvana, etc. etc? I could go on.
In none of those scenarios is the Christ-follower to be worried about either suffering punishment for being incorrect, and actually in most he is rewarded as well as those who were right. Surprising, right?
My main point is just that it's logical to choose to follow Christ just based on risk/reward, though that would hopefully just be a starting point. The reward being eternal, infinite bliss, and meaning and purpose for the life here in the meantime; the risk being that another religion (or none at all) is correct: the result would be, for the Christian, perhaps not having an afterlife at all (atheism/some forms of Judaism/Shinto), or being in a lower form of paradise (Islam/Mormonism/Tibetan Buddhism/debatably: Daoism/Zen Buddhism & Sikhism (Nirvana)/ Western Pure Land Buddhism/forms of Hinduism/Baha'i/Jainism). I tried to cover the major world religions, and ones I've studied, but if I let any out I apologize. Some of these specify Christians as landing in a form of their heaven (Islam, Mormonism, Judaism, at least some forms), while some prescribe universal salvation.
All that being said, I'd just challenge my skeptical friends to ask God a simple request after reading this. Just say something like "God, I don't believe you're there, but if you are, please show me in a way I'd believe - because if you are, I don't want to be wrong about it... thanks." You really have nothing to lose, especially if you're wrong. And I believe God raised Jesus from the dead; if he can do that, he can make something happen in your life in the coming days, weeks, etc. to show you he's real.
Happy lent, all.
