We like to do this for Halloween
Can of Fruit Punch
Can of Pineapple Pieces
Can of Fruit Salad
Peeled Lemon, cut into slices
Peeled Orange, cut up into slices
Assorted fizzy fruit flavoured drinks
Mix together a bit at a time until it tastes right. Make sure you put it in a big bowl with some room to spare. Then add a fist sized piece of dry ice. (Do not touch with your bare hands- wear winter gloves and use tongs) The drink will bubble and a fog will come out of the bowl. This is Carbon Dioxide. so it isn't poisonous- it's what you breathe out all the time. Still, have doors open to other rooms if you are worried. The fog can be scooped up with a ladle and poured into glasses- kids really have a lot of fun with this.
Obviously you'd want to be careful that you don't swallow the frozen dry ice. That's why you put big chunks in, rather than smaller ones. You can find dry ice by looking in the yellow pages- they give you way more than you need, but that's OK- just keep it in the freezer, and you'll have enough to use at night. By morning of course it will all be gone.