I began to doubt god's existence around Christmas 2009 when I was struck with a simple thought: I wonder if anyone besides the gospel writers wrote about Jesus?
I simply googled it and read. I was honestly shocked. I don't recall which websites came up first, but some mentioned sources in a positive light (supporting Jesus being who the gospels portray him as) and others in a negative one. What struck me was that even granting that at least some did write about him, I found two radically different portraits.
On the one hand, from the gospels, I had a man whose "fame spread" throughout many lands and to many ears (Mk. 1:28, Mk. 1:45, Mt. 4:24, Mt. 9:26, Mt. 9:31, Mt. 14:1 to name only a handful), who ministered publicly for 1-3 years (synoptics vs. John), who conducted many amazing miracles (healing of blindness, leprosy, raising several from the dead, walking on water, controlling nature), and spoke words which many thought of as simply incredible.
On the other hand, only a few contemporaries felt the need to write anything about Jesus and all that made the cut was essentially that he lived and had followers? There is much debate about Josephus; surely he confirms Jesus' existence but it is anything but resolved as to whether he held that Jesus might not have been a man, did marvels, and was "the Christ."
In any case, this troubled me deeply. I felt physically nauseous for my first days of doubt. I didn't know how to tell my wife or anyone else. I finally did and was not received warmly. See, when doubt ensued, I decided to plunge head first into research and study to establish whether god existed or not. As with any other research endeavor I have undertaken, I try to suspend preconceived notions and establish the truest opinion I can form based on evidence; I try to avoid personal preference or group consensus as swaying inputs.
My initial thoughts when pursuing this question were:
1) The best way to decide if Christianity is true is to assume that it is false and try to prove it to myself
2) If god is the author of all truth, I cannot end up anywhere but back at him in this quest
3) God would not be disappointed in me for pursuing the truth and should I establish that Christianity is true, I will be a stronger believer and evangelist than ever
A note on #3. In looking back over my life, it became very obvious to me that I had avoided evangelizing the "un-evangelized." When working for a Christian missionary group in college, our goal was to evangelize. Never had I felt comfortable trying to do so with those who did not already identify themselves as some form of Christian, even if they were not being very good ones. If someone was a Christian, it was a lot easier to invite them to a talk or prayer group; if someone was not a Christian, I had always felt at a loss to establish persuasively why they should be Christian and not what they already were... and so I never trod on that ground.
Once I realized this, I decided I never wanted to have unfounded beliefs again. I wanted to know why I believed what I believed. I wanted to believe in whatever was the surest form of reality that could be established by evidence. I wanted whatever I believed in to be objectively and externally available to anyone else who wanted to see or experience the source of my evidence.
Thus, my quest began. I have read and read, listened to countless debates and interviews, and I became fairly involved in the blogosphere. I have set a deadline of Christmas 2010 for my decision. I will read and ponder and receive prayers and try to even pray myself in an attempt to come to a clear decision.
As of July 2010 I have no intellectual belief in god anymore. Emotionally I feel the obligation to continue reading in order to give Christian apologetics a chance and see if there is any hope for reconciling my questions and doubts. I remain unsure of how to proceed as I feel that my options are between leaving Christianity or swallowing a massive horse pill of possible solutions without any evidence. This seems like an extremely difficult position to be in. God could, after all, be true... but the way in which I was made (a critical, doubting, skeptical, studying, researching individual) is asking quite a lot when it comes to belief literally without any supporting evidence but a text (which is a source of doubt in the first place).
I have decided to undertake the Ultimate Truth-Seeker Challenge (Easy Version) as part of my activity in the next months. I'm not sure what else I will attempt. Coming from Catholicism, it has occurred to me to "go out with a bang" and attend confession, begin attending Mass again for the last x months, trying to pray every morning, or something like this to see if anything happens.
At present, the best prayer that has come to my lips is, "Jesus, give me something I can't deny". I believe this is extremely accurate and to the point. God knows me better than I know myself. Thus he knows what my genes, past experiences, and environment has formed me to be at present. He simply has to provide me with enough to convince me of his existence and I will believe.
It's that simple.
 My progress and notes to the books I read may be found at my Truth-Seeker Challenge summary page.