Using a large washing machine type box, draw a dinosaur on it. In the middle of the dinosaur's body draw a target using 5-6 concentric circles. Give each circle a point value. Give the first boy 3 darts (suction cup type) and on signal, he is to throw the darts at the dinosaur and score points.
Or cut out the shape of a dinosaur from cardboard or wood. Paint and decorate the cutout. Hammer nails into the dinosaur at different places. Mark each nail with a point value. This is the target. Place it 8 to 10 feet away. Have each boy throw rubber jar rings at the dinosaur with intent to ring the nails. Score one point for each successful ring or add up the number value.
Another version of this same game could be to give different parts of the dinosaur different point values. Draw a target with 4-5 small rings and give each ring a point value.
Example: The head could be 20 points, the legs and arms could be 10 points, the eyes could be 40 points, the tip of the tail could be 30 points, etc. The highest score after three throws is the winner. Or make up your own ring toss variation.