When kids grow up these days, they do not discard their affection for Halloween. The ancient holiday remains wonderful fun for kids, and adults indulge in the annual revel as well.
I think three things make Halloween fun. The first is a feeling of community. This emerges when people go out into their neighborhoods with their children to trick-or-treat. When else do Americans run up and down their streets having fun and passing out candy? This activity helps people feel connected to each other, which is a basic human need. Even people without young children can participate by passing out candy. And often, merry parties are going on within homes as the doorbell rings. And party hopping among adults as they go from one costume party to another goes on late into the night after the wee trick-or-treaters have been tucked in with their candy bellyaches.
The second aspect of Halloween that makes it fun is costuming. This is a centuries old method for making merry. Costumes allow people to loosen the hold of their inhibitions. A costume allows someone to feel the excitement and freedom of living within an alternative identity. Costuming also lets people explore other aspects and interests of their personalities.
Finally, Halloween allows people to enjoy being scared. Most people like the feeling of fear based on something that is not actually real. It releases a pleasing adrenaline rush. The scary and spooky elements of Halloween celebration also carry on the ancient traditions of recognizing death as part of the world. Halloween can represent the death of one year and the birth of a new year, and it also draws liberally upon traditions that honor dead loved ones once a year.
I produce a Halloween website called Making Fear Fun with helpful information about many aspects of celebrating Halloween. If you're still working on putting a costume together, I recommend the following articles:
Five Top Tips for Saving Money on a Halloween Costume
Fast Low Budget Costumes