If you ask kids what their favorite holiday is, the most likely answer from most kids will be Christmas, with Halloween a close second. A few kids will select Halloween as their first favorite. Only this holiday, with all its ghouls and goblins, likely makes the top two favorite holidays on most children's' lists.
For younger kids, what about a game of pumpkin bowling? Buy some of those cheap plastic pumpkin treat buckets and pile them up on a hard floor. You can pile them as high as you can, but you have to start with at least three buckets. If you get a lot of buckets, you can create a pyramid out of them. Find some light plastic balls - plastic bowling balls are great for this. And let the children go bowling! Children love bowling over the pumpkin heads and all the kids who play ought to win a prize for this game.
Kids of all ages love making mummies out of themselves and their friends. This is how it works. You get a toilet paper, lots and lots of toilet paper. Separate the children into teams of 2. Once you start timing the kids, they should wrap their friend up in the toilet paper, mummy style. The first team who's all wrapped up wins. The kid who's wrapped up like a mummy can now break out of the toilet paper wrap with a scary "roar" and then the game begins once again so the other kid could also be wrapped. Make sure to play some spooky Halloween music when this game is being played to add up to the atmosphere.
Circle time! Have all the kids form a circle and start out a spooky story. The tale can begin with the classic, "It was a dark and eerie night..." And so the person next in the circle keeps on the story. Each child adds up something to the story as it proceeds around the circle. If the kids are young, you can keep on the story on the straight and narrow by pointing no gruesome elements will be allowed for. If the children are older, you can choose how scary the story can be. Be aware that kids in higher elementary grades won't only like their stories a bit scary and gruesome, but a few may even add "booger" and "snot" and "throw up" factors to their story. Set the rules ahead of time to prepare for this type of storytelling.
No game has held onto kids liking for a lot of years than the classic "musical chairs". This adaptation includes playing Halloween music (think "Monster Mash" or "Thriller" by Michael Jackson) and requiring the kids to act as spooky and scary as they can when they go round the chairs. You can up the rules based on the ages of the kids. For instance, for kids in the lower grades you can tell them to just walk about the chairs until the music stops. As they get older, you can add up challenging factors, like making scary faces as you walk around the chairs, do the monster mash (whatsoever that means to the kid) and extra things like that. You are certain to get some creative reactions.
Children love cakewalks, but they aren't practical inside the classroom. You could, nevertheless, have a treat walk. Hold open enough space in the classroom for this one. Once again, play some Halloween-themed music and have the kids walk about in a circle as they do for cakewalks on other school events. Rather than letting them walk onto number squares or circles, you can have them walking onto cardboard saucers that have pictures of ghosts, monsters and the like. The individual running the cakewalk should stop the music and pull out a matching picture out of a pumpkin head. Rather than calling "#14", for instance, as the winner of the cakewalk, it will be "ghost head" or "monster mouth".