Design Exploration ~ Interactive Instruction

I am interested in utilizing the web to teach secondary math skills. I searched for examples and found the following: www.mathbits.com/caching/opencache1.html (a caching game with multiple choice answers and a "certificate" at the end) http://www.factoring-polynomials.com/ (gives a book like description on how to factor, no practice problems) http://www.quia.com/rr/36611.html (a seeminly endless supply, of multiple choice factoring problems, but with no instruction), and finally http://glory.gc.maricopa.edu/~amckinto/Bottoms%20up.htm (a site that explains the “bottoms up” factoring method and gives a couple of examples.) These sites use a book-like format for instruction and give sample problems with "right/wrong" as the only feedback.

I think it would be really cool to go a step further by using the multi-media and interactive capabilities of the web to make learning math skills interesting and fun, and, more importantly, give interactive initial & intermediate instruction and hints to help when they get stuck. A perfect example of this in the on-line Sudoku game on http://www.learningplanet.com/. This Sudoku game incorporates many multi-media aspects to make the game fun (time clock, interesting graphics, theme) but most importantly, the game gives interactive instruction (see "how to play") and provides intermediate feedback throughout game play. And, there is unlimited number of games to play. The elements of this Sudoku game could be applied to teaching math skills on-line.