Mensa has free lesson plans online.

I also like UC Berkeley and MIT's free webcasts:

http://webcast.berkeley.edu/
http://ocw.mit.edu/OcwWeb/web/home/home/index.htm

Hippocampus also has some good stuff.

I have a lot of free curriculum listed here and free online educational games here. I tried to only list ones that I thought were worthwhile.

Study Strategies for Accelerated Learners