Children carrying flowers, making music and singing songs. Have a traditional Wursttable. Different kind of sausages nicely arranged that can be heated or barbecued. For this, gingerbread hearts can be baked in advance and decorated with sugar. Any message that strikes the children's fancy.
Children can make and sell the lemonade.
With luck, you will have a parent who can bake some apple strudels, German cookies and a kirshtorte or any kind of fruit or marzipan cupcakes or pastries will make it very special. If you have gymnasts in your school, feature them. No Oktoberfest is complete without singing and dancing. Have your children form a choir, Sangerchor in German and entertain your audience. There are many bands and choirs in America.