I recently came across MathCentre
which has a biggish collection of free maths materials aimed at 16yos and above - but in a style that seems very suitable for many of our children. I've only started to browse but in the best covered topics they have teach-yourself documents, revision question sets, quick reference documents and the odd video lesson. The things I've checked out are clearly presented, precise and concise enough to make you weep when you go back to many school textbooks. Enjoy :-)

Thanks -- the site looks useful.

These really are beautifully presented. Clearly explained. I will be using one of them tonight to help older dd study for an Algebra test. Highly recommended.
Thanks for posting, ColinsMum!!

It's a great site. Thank you.