According to Wikipedia, "Easter is the most important religious feast in the Christian liturgical year. It is believed by the Christians to be the resurrection of Jesus, which Christians believe occurred on the third day after his crucifixion around AD 33."
In fact, it might be said that Christianity stands or falls based on whether or not the resurrection of Jesus actually occurred.
The "evidence" is sketchy.
The primary "evidence" comes from so-called "New Testament" biblical texts. We do not have the original copies of these texts. The earliest sufficiently complete copies we have come hundreds of years after the supposed events. They are fragmentary and are copies of earlier copies, which are themselves copies of earlier copies, and so on, to an unknown degree removed from the originals. Comparisons of the various copies that we do have show variations between them and indicate that copying errors occurred.
The sudden appearance of new sections of text in later copies (text that doesn't appear in any earlier copies) indicate that some things were added later and were most likely not contained in the original versions. This opens up the possibility that additions were made before the earliest copies available to us as well.
Even the originals, from which the flawed copies are derived, were written decades after the supposed events took place. None of them were likely written by actual eye-witnesses, so they are second-hand accounts at best. They are likely even further removed from the supposed events than that, either based on prior writings that are lost to us and/or oral traditions that were passed down over time. [The reliability of stories passed down orally is suspect to anyone who has ever played the game "Telephone."] Additionally, the original authorship of the various texts is either entirely unknown or speculative.
The various texts that we are left with are in conflict with one another in many of their details regarding the events that supposedly took place. They also sometimes apparently conflict with what we know about the history, culture, or traditions of that time, place, and people.
They include accounts that are suspiciously similar to other earlier stories that were told about other god-men that we now consider mythological, and these accounts claim various extraordinary and supernatural events taking place that most of us would consider wild, outrageous, and even unbelievable were they to be told about something happening in today's world with no more evidence than what we have here.
Even if we assume that Jesus existed and that the whole story wasn't an invention, distortion, or in any way embellished, that the written translations were more or less uncorrupted and somewhat accurate translations from the original texts, and that the original texts were based on accurate reports of more or less uncorrupted and somewhat accurate oral accounts given in good faith by actual eye-witnesses (which is quite a lot to assume), there is still the possibility that the witnesses were mistaken or deceived.
So we have flawed translations of conflicting reports by anonymous authors who were relaying second-hand hearsay-accounts of wild, extraordinary, and supernatural events given by unsophisticated witnesses, who were possibly duped, mistaken, or lying (if the authors themselves weren't fabricating or embellishing), and that are suspiciously similar to earlier stories circulating at the time which we now consider unbelievable mythology.
This kind of "evidence" would be laughed out of any court of law today.
It is certainly not much to base your life on.
Occum's Razor and common sense suggest that there are any number of other more rational/natural explanations for these accounts of supposed events than the one Christians believe.
I think it unlikely that most Christians would even believe it, if they were presented with this evidence for the first time as adults and not brought up to believe it as children when they were most impressionable.
In some ways it seems strangely appropriate to celebrate this day with painted hard-boiled eggs, chocolate, and bunny rabbits. I mean, if we are going the irrational route, why not? At least it is a more pleasant combination than celery, grasshoppers, and motor oil.
