Skylanders party! Chompy piñata, kaos and pop fizz decorations. Used balloons and paper mâché (newspaper strips dipped in flour/water). Bought tissue paper and cut into strips to cover the paper mâché, then construction paper for eyes, ears and arms. Very cheap to make!
It's called a "Punch Box" and it's a great alternative to a pinata. (Four-year-olds with big sticks can be a little scary sometimes.) Instead of beating on a pinata with a stick, each child punches through one of the pretty colored circles in order to grab the prize inside.