I use to have parties for my children when they were young and thought I'd share some party ideas:
My first idea is to have a "pumpkin patch for the kids" by making pumpkins with a prize inside the pumpkin. Place the pumpkins around the yard and let the kids go "into the pumpkin patch" and pick their pumpkin. Then they open it and get their prize. Especially good for young children.
Next, I like to provide each child with a candy cup such as the one shown below. This allows them to have a reasonable amount of candy instead of overdosing on it.
We also use to play a lot of games like bob for apples. To add some extra fun, before the party I would thoroughly wash some coins and insert them into the apples before they bob for them. It's important to have an adult take the coins out as soon as a child catches their apple. I use a butter knife to do this.
Then there is always the eat the donuts off a string. We would tie plain cider donuts to a string and tie it across the room. Kids would hold their hands behind their back and see who could eat their whole donut first without touching it with their hands.
Also, I never liked the game of musical chairs as someone always would get shoved on the floor so instead we would draw or cut out Halloween themed pictures and paste them to pieces of cardstock and lay them on the floor in a circle. Also, write the name of each picture on an index card (such as pumpkin, black cat, witch, broom etc). Turn on some music and let the kids march around in a circle just outside the pictures that are on the floor. When the music stops, each child steps onto the picture closest to them. Then you choose an index card and call out the picture. Anyone standing on that picture gets a small prize. If you do not have enough pictures for each child to stand on their own picture, let two children stand together on a picture but both would get a prize if that picture is called.
Hope you can use some of these ideas if you are hosting a children's Halloween party