I found this challenge to be very much worth my while.  I think the most valuable tool for me will be the worldbookonline site.  So much information there and neat things for the kids to use, especially for those who struggle with reading.  Also the pictures, music, videos, other websites it suggests.  Very useful and easy to use.  I also really like the Mango Languages site and the Ancestry site.  Honestly more for my personal use than my students, but Mango would be really good for a student with English as a second language.

I have already shared/showed a few of my colleagues some sites that I have researched and they seem interested as well.