I forgot what site this one came from but take a 2 x 4 and cut a groove down the length of it and you can wedge saltine crackers in the groove. One box will give you a good supply of targets and the animals will clean up the crumbs overnight.
R/C car with a dowel or coat hanger sticking up. Tie a balloon to the top. Drive car back and forth and try to hit the balloon. When that gets too easy, tie on 2 balloons of different colors and make 1 a no shoot.