I've seen a game that is played like horseshoes, you take 2 one pound coffee can and bolt them into a box that is 16" X 20" X 3-1/2". Make the bottom out of OSB or scrapes of plywood. Get 1" diameter flat washers, 6ea and paint 3 one color and 3 a different color (or mark them as sets of 3 someway) Place the boxes a comfortable distance apart and throw the washers (two teams of two people each) throw the washers and try to get them into the can. 3 points for each one in the can and 1 point for each one in the box. Lots of fun, easy to make, and can be moved to stay in the shade. Have several games made up and get some competion going.
Also, attach two golf balls to a 12" piece of cord. paint one set a different color. 3 ball/cord set. Make a PVC (1") stand with one level at 18" and one level at 36" (shaped like an U upside down with a bar across the middle) attached to something heavy to keep it upright. Place the stands pararell to each other and throw at the other stand on the opposite end. The balls will wrap around the cross pieces, give 1 point for the top bar and 2 points for the bottm bar. Go to 11 in both games. This is played the same as the washer game. You can't step past the goal on the throwing end.