I use this in my high school classes Algebra classes, I might have used it one time once in a summer math 121 course.
(1)I first everyone get out two pieces of paper. I want everyone to make up two binomials and multiply them. I do reguire them to make sure that the binomial terms do not have a common factor. I also tell them to not use any numbers larger than 10.
(2)Then I want them to double check their answer and write it on the other sheet of paper and number it as problem #1.
(3)Then I have them repeat the process at least one more time.
(4) Then they are to give the piece of paper with the problems to another class member and they try to factor the problems.
I have modified this sometimes to make a game out of it where you earn points if you stump someone, you earn points for factoring the problem.
Sometimes I make the competition in teams and some times it is all individual and students can earn a few bonus points on that paticular assignment.