Tetris using Arrays! Students roll double dice and those are the dimensions. After they create the array they have to write the multiplication problem with the total number. To add more difficulty they have to label if the number is a prime, square, or composite! If they fill in the line on the tetris board they get a point!
I use this project when I start my multiplication unit to teach repeated addition, groups of, commutative property, and arrays. You could also replace one with a multiplication word problem and picture.