Van Leeuwenhoek's primary journals are found scanned within this 516 page eBook. For me, far aside from content... I would use this resource when coaching students on interactive science notebooks. His handwritten/drawn documentation is still a model today. To day we could use a digital camera, back then... he WAS a "camera." So cool.
Neat interactive site showing where different species are located on North America. You can search by species, search their family tree and search conservation status.
The emerging set of interactive simulations at PhET that now use HTML5 and work solely within a modern browser. These are heavy in the physical sciences... but also include acid-base, atomic structure, chemical equations, etc.
A vernier lab using heart rate monitor for human body unit. Interaction between nervous system and muscular system in response to a stimulus. Pretty darn cool lab!