The basketball addition multiplication game evolved from an old flash basketball game. The essential concept was to tie each made shot to a number of points. In this way, in order to tally up your points you need to add the same number over and over again. Which creates a nice transition between addition and multiplication, because you can either add them or memorize the multiple of the number.
Even if you don’t know the multiple, the concept of multiplication has been introduced. It also ties in nicely, if not precisely with the basketball metaphor that shots farther from the basket are worth more. Thus on each of the five levels the player moves further away from the basket, changing the points value and raising the difficulty of adding up the numbers, reinforcing the value of knowing the multiplication table for that point value.
To improve on the old flash game, it occurred to me that I could put invisible rectangles around the basket that would deflect the ball unless it was launched in a proper way so it would fall through the net. This game play was further enhanced by implementing a physics engine to make the bouncing and falling more natural.
Overall it turned out to be a good synergy between a popular sports game, the interactive game mechanics and a math learning goal.