This is a great resource for teachers studying Explorers. Its an interactive map that actually shows all of the routes taken by European explorers during the Age of Exploration.
This is a site that provides a great number of study aids for biology and anatomy teachers. I've used the site as a great way to lead guided practice in my classroom by playing the review games as a class, letting individual students come up and fill in answers. The pictures alone are fantastic for teaching everything from the skeletal skeletal sustem to histology.
This is a great resource to allow students to work at their own pace. It reinforces quick recall of addition, subtraction, multiplication, and division problems. It is great for both elementary and middle school students.
Several types of concept maps (in INTERACTIVE pdf format) This means you can link to them, students can access them, complete them, save and turn in electronically. They can also be downloaded and printed if there's little to no access to classroom computers.
Or do some collaborative/small group work. Have small groups of students complete a task, work together on completing and explain/defend their concept map to whole group.
Non-linguistic representations are a high impact teaching strategy that work especially well with visual learners. Consider using these for organization, pre-writing, summaries, etc.
Excellent interactive planner for scholars in grades 1-5. It defines the steps needed to conduct research in developmentally appropriate concrete and sequential terms.