This one is a "you got to see it to believe it". Talk about a gold mine for graphic organizers. There are templates for source analyser, priority chart, jigsaw diagram, learning cycle, living graphs, venn diagrams, fishbone, flash card generator, random name picker, and random timer and more.... I have used this to teach my students how to use graphic organizers and at some point another class found them as well. They are interactive, for example, you click inside the venn diagram to fill in similar or different ideas for two comparison items.
You can print them, or save them with an account (it cost money) or you can take a scrren shot (that's what I do with my kids) or even better, download it into a web site to add to their web site. My students rather use these ones then do one on paper.
The next best thing that is on Classtools is a random selector and their latest thing, FakeBook - like Facebook it is a wall, but you make up the characters to do their profiles. You can use this tool to discuss historical events for formative assessment. You can get students to use critical thinking skills, having characters in a book discuss plot, reasoning behind actions, etc. This tool can be used for a number of things and if you get an account (yes it cost money), you can save these walls, or in the end just print them out and give them to your teacher so he/she can assess learning.
This site is a treasure trove of assessment. In the end you can put them on your blog, use them for e-portfolios, and more. Thanks ClassTools Russel Tarr. He's on Twitter.