I had the opportunity to tweak one of the Dynamic Number project's sketches yesterday. Zooming Integers provides an interesting display using an exploding or zooming number line. In Ontario, we use spaces rather than commas to separate digit groups (see http://physics.nist.gov/cuu/Units/checklist.html). Our Grade 6 curriculum includes millions and the sketch only goes up to 100 000. I was able to copy the 100 000 page, change two parameters (with a little digging) and get a page that starts with a number line from 0 to 1 000 000. Ontario benefits from having a provincial license for The Geometer's Sketchpad so that students can access this material.
You can access the tweaked sketch from here.