Here's a version from Kraft foods:

9 cups popped popcorn
1 cup light corn syrup
1/2 cup sugar
1 pkg. (4-serving size) JELL-O Brand Gelatin Dessert, any red flavor (substitute green)

Place popcorn in large lightly buttered bowl.
Mix syrup and sugar in saucepan; bring to boil. Remove from heat. Add gelatin; stir until dissolved.
Pour over popcorn, mixing well. Cool about 5 minutes. Shape into 2-inch hearts (shamrocks?) or balls.