I have been a room mom for many years! My two favorite games are Classroom bingo (bingo cards with kids names in each square. If you are creative, you can make these. I do this for Valentines Day and use the conversation hearts for markers.) "Halloween horror/ find the body parts" is my favorite. Halloween golf is fun. Pass the skull (hot potato with a group of eight, is good.)
If you have a total of 4 room parents, ask each to make 2 lbs. of spaghetti,add a little oil and refrigerate, one or two nights before, in a plastic bag to bring to the party. You can also make 2 -4 lbs.
HALLOWEEN HORROR - MAKE AT HOME:
Use a large box, cut two arm holes on the sides of the box, so there are 8 holes total.
Next, line the box with a huge black, plastic, garbage bag. Fit the bag in the box. Using a hot glue gun, outline the inside of each hole and let the plastic bag stick to the box. Do not cut out plastic in hole, just make an X in the plastic (it prevents kids from seeing what's inside). Make sure lid can overlap shut. No need to tape shut.
You can either make this a timed game, using one box, (two minutes each team) or have three teams (8 per box) and play it all at the same time. An easy way to divide up teams is making name tags BEFORE the party - 3 holiday/colors/ shapes (or the school may have a die-cut machine) and print kids names on labels. An extra set of labels is helpful to put on any goodie bag.
Look for rubber body parts - Target used to carry them. For one box, you will need to put 15 items+ per two pounds of spaghetti. (Presort so you have even numbers, if you are using 3 boxes because kids want to see what is going in...don't let them!) I also throw in a few small rubber mice, bugs, etc....Just dump the spaghetti, in the box, mix the parts in the spaghetti and close the lid.
Target used to have 1" feet, noses, eyeballs, and hands. If you can find something like this, great. This gives you an idea what they look like.
Bring newspaper or plastic tablecloth to cover table.
My rules are, if a kid removes something that is not a body part, that person becomes eliminated from the group. Also, if anyone removes spaghetti (like a handful), their turn is also over, immediately, (Keeps kids from throwing around spaghetti!) Also, NO PEEKING - one adult can monitor each team.
Wash off body parts and keep for years. Leave boxes and old spaghetti, at school to toss.
I've done this sooo many years. When the kids are in 4th grade, I usually make three boxes (your local grocery store can find large boxes but you might have to wait a couple days for them.) Or, I buy moving boxes from Lowe's or Home Depot. I place one box on a desk and let the kids gather around it.
Kids love games at this age. Some kids are a little squeamish but still like watching.