I have my son who is 3, an annual Halloween party each year and it only gets better every year.  I started this year with making the invitations.  I used plain (no lines) index cards and turned them long side up.. I printed them with BOO at the main top and then proceeded with the invite to say It's that time of year again place and time) so put on your costume hop on your broom and fly on over for a great time!!!  Underneath the words BOO I glued wiggly eyes and then wrapped the invititation with gauze to look like a Mummy.. So when the recipient received the invite they would have to unwrap it to see what it said. We always have the party at a local school so at the entrance to the school I have a HUGE blow up Haunted House that you can walk through that lights up and plays scary music so I put it at the door so the guests would actually have to walk through it to get in.. The kids loved it.. I also have a fog machine that I put near the house so it would give it a more eery feel. I decorated the school gym with different blow up characters pumpkins cats etc.  I always use plenty of Balloons Frankenstein Spongebob Charlie Brown and the Pumpkin Patch etc. I use black and orange and purple tablecloths with matching plates silverware etc.. all can be picked up at the Dollar tree very inexpensive.. For games I try to include all ages as I have from 1-13 year olds there I have a fishing game which I put a large blanket over tables stacked up (the school had these in the gym and it worked) My husband gets behind their and as the kids throw their line over he "hooks" it with a small prize.. the kids love this too.. I also have a Pumpkin potato sack race pick a rubber ducky for a prize a cake walk and I have a donut eating contest for the bigger kids where I hang donuts from the monkey bars and the kids must eat the donut with no hands.. it turned out to be very tricky. I always order small prizes from Oriental Trading they are perfect.  The food I serve is always Halloween themed I have mummy wraps (weiners on a stick wrapped with breadsticks) Goooooulash for the adults Bat Puke (a salsa style dip) Frankenstein's Brains (jello with brain mold) Frankenstein's hands (jello with hand mold) BOO kids (white chocolate covered Nutter butter cookies with 2 miniature chocolate morsels for eyes) Witches' fingers (popcorn in clear plastic gloves tied with a small ribbon) Witches' Brew (punch) I have a cauldron that plugs in that looks like fog I place near the punch it is a cool effect) and I put different juice boxes koolaid drinks bottled water etc. in a large tub (I bought at Wal-Mart for 3.00) with ice and the guests can help themselves I also had a huge Chocolate chip cookie that was decorated in a Halloween theme for dessert. After everyone ate we had a Hay-ride through the community the kids love this too.. a couple of adults always hide along the path and jump out and spray silly string on the kids they think this is something!!! I then hand out the treat bags which are made of candy more toy items from Oriental etc. This was my third party and as I mentioned it gets bigger every year I had about 40 guests this year and the funny thing was BOTH parents came with each child.. so I think that the adults enjoy it just as much as the kids.."