A balloon bouquet of smiling dinosaur (or other animal) faces tied to a mailbox makes a fun greeting for kids arriving at a party.
Later, you can let each guest take one home.
Inflate a bunch of quality large round latex balloons or, even better, purchase helium-filled balloons at a party store (generally, they cost about $1 apiece).
Turn each balloon knotted-side-up, then pull the string down along the back and tape it to the bottom of the inverted balloon.
With acrylic paint, decorate the front of each balloon with two large eyes, circular nostrils, and a U-shaped row of zigzag teeth.