I linked to some of MythVision´s skeptical-minimalist Bible documentaries before. Here, he discusses what would make him go back to Christianity. Spoiler: probably nothing at this point.
I would be convinced that "God" or "the supernatural-spiritual" exists if I had a very strong experience suggesting just that. Not sure what would convince me of Christianity specifically, though. Or American evangelicalism in particular. Even a strong experience of Jesus could be interpreted in a pluralist manner, after all. Especially if he comes draped in the Star-Spangled Banner! I mean, why not the flag of Vatican City, huh?
For discussion purposes. The floor is open.