Prime Factor Visualization
This really is an exciting time in the history of ideas.
Like cars and VCRs had to wait locked up inside mountains for eternities waiting for the world to be ready for them while dinosaurs and people dabbled outside, the boundless and beautiful magic of numbers (like so many other things) has largely been contained by shelved text books and erased chalk/white boards, accessible only to those willing to sit through years of hit-and-miss teachings before they get to imagine a glimpse of the truly amazing fun parts.
That is changing rapidly with the advent of readily available interactive media (think: interactive web page on iPad screen in hand of kindergartener) and some really simple and elegant free open source solutions for translating abstract ideas into rich interactive visual models (ie: d3/coffeescript/knockout web app supported by cloud based open source server stack).
Now, you can take something like Factorization and build an interactive visual model which reveals numbers and their multiplicative relationships in a way that is fun to play with. There is nothing to install, nothing to explain. in fact, words would probably get in the way.
Our factorization demo can be found at http://www.zeebar.com/demo/multiples
Please enjoy and email your feedback to firstname.lastname@example.org