If the party is for a young child which I believe it is, a good idea is home made crowns and tiaras. This would be fun to do with the child. There are a few ways, but I remember back in science class we grew crystals, and when I read your questions I thoguht Hmm? What could you make? Then I remember growing crystals and it all went together. All you'll need is a variety of pipe cleaners which you can find extremely cheap at a Dollar Store or Drug Store, and Borax Laundry Detergent(Powder form), that might be hard to find, But I'm sure your searches will end at Wal-Mart, water, a baseball bat, a big pot and string. How would you grow these crystals with Laundry Detergent, string and water? Simple.
Have the kid, with your help make crowns and tiaras for his/ or her guests out of pipe cleaner, you may find this hard and frustrating, but your spending time with the child atleast and in the end I believe you'll trully love your creation. When you have made them
Tie the strings to the end of one of the crowns or tiraras. Tie the other end of the strings to a baseball bat or item long enough to strech across the pots. You want the lengths to be such that the baseball bat hangs the crown or tirara into the big pots. Fill the pot with boiling water. Add borax one cup at a time to the boiling water, stirring to dissolve after each addition. Untell no more dissolves, It is okay if some undissolved borax settles to the bottom of the pot. If desired, you may tint the mixture with food color. Hang the pipe cleaner Crown or tirara into the pot so that the baseball bat rests on top of the jar and the crown or tirara is completely covered with liquid and hangs freely (not touching the bottom of the jar). Allow the jar to sit in an undisturbed location overnight. In the morning youll have a BEAUTIFUL crown. Or you could just make one for the birthday boy/ or girl. Twist up my idea into your on, theres so much you could do with growing crystals you could make jewlery too.