K.K.
Is this to keep kids entertained while General PTA meeting business is going on? Low mess arts and crafts. Wire bending is fun. Coolect recylable trash in big bins and give them tape to make stuff. At our art fair it was the most popular table, just rash and tape. Cardboard boxes and shoe boxes turned into robots, etc.
Find out wear you will be keeping the kids, do you have access to TV and dvd's? You can get some science/art stuff to do demostrations for them at USA toys store. Has anyone ran this program for you? I am assuming your budget is for the whole year?
Volunteers, you will need a few, and a least one person willing to deal with the rowdy uninterested kids.