Jefferson Lab is a good place to find educational online games and puzzles. I initially discovered this resource a couple of years ago when one of my students played "Who Wants to Win $1,000,000?" during a study hall period, she had learned about it from one of her other teachers. The games and puzzles on the Jefferson Lab site are math and science games with one word game thrown in for good measure.
This is an online course called the Habitable Planet. Users can select content by unit which lists all of the topics coveredn in the course or content by type which lists what is available to users. The content by type includes the online textbook in pdf format, videos, interactive labs, visuals, scientists, professional development guide and a glossary. It looks very organized.
"Arcademic Skill Builders are free research-based and standards-aligned educational games! Engage and motivate students with our multiplayer and single-player games." As of August 2011 Academic Skill Builders has released 40 web-based learning games designed to help K-8 students build basic math, olanguage arts, vocabulary, and thinking skills. The games incorporate multiplayer capabilities in educational gaming. Studetns can play together in groups of 4, 8, or 12 at a time, promoting positive interaction and achievement. Educators can use the free arcade-like games with a projector screen, interactive whiteboard, or computer lab. Security safeguards ensure that no one outside the classroom can contact students who are playing the games. The games align with state standards and the Common Core Standards.
The online writing lab provides a variety of resources for use with research. Includes writing citations as well as resources for subject specific writing.