Halloween is probably one of the most fascinating holidays in my opinion (as well as one of the best); it's known by many different names, some are All Hallows Eve, All Saints Eve, and/or Samhain.
Beliefs regarding this day range in diversity and have changed drastically over the years. But all traditions carry the basic theme that during this night the veil between the world of the living and the world of the dead are thin, which with some beliefs, enables those that have passed on to the world of the dead, to come back on this night--usually for about three days, the day before Halloween, Halloween, and the day after.
Some countries light candles and place them on a window sill to guide spirits of loved ones home, others leave food on the porch for any hungry spirits, and one story I've heard stated that towns, people will gather with torches (the light attracts the spirits) and they will march with the spirits out of town. The draw back 'the veil thinning' is that evil spirits can cross into our world too. And that is where the carving of pumpkins and turnips, and dressing up comes into play. It is believed that dressing up as something 'supernatural' can hide you from evil spirits or that dressing up or --'gusiing' as it was once called-- scares them away. As said, the beliefs on this differ widely, and some of the more fascinating stories come from older traditions. The most common thing to do is crave!! Whether it is apples (to tell your future), or pumpkins and/or turnips (to scare away evil spirits), carving is one thing that all celebrations tend to include. Including our modern traditions. Even though our modern traditions have changed over time.
Anyways, whatever your traditions and/or religious beliefs, and whether or not you buy into any of these out-there beliefs and traditions I hope you have an awesome, safe Halloween night, eating candy, trick-or-treating, and "using humor and ridicule to confront the power of death."