Use Our Courts as a great civics resource. Included among the games are many lesson plans written for all grade levels.
You have to click a few layers down to get to the good stuff, but LearningScience.org does have lots of links to online science interactives.
Today’s snow reminds me of one of my favorite sites…and I probably haven’t shared it for a while. SnowCrystals.com.
If you’re interested in exploring ways in which your students can write online with blogs, check out Kidblog. You can set up controlled blogs for your students without them needing an email address. Kidblog defaults to allowing only classmates to view blogs.