This site is an excellent series of free online tools to explore for use in your classroom. Be sure to add those items that would be useful in your classroom to this diigo site.
Hippocampus in partnership with MoVIP offers free online curriculum for a variety of courses. You can create a logon and use these online materials in your classroom. You can also bring the videos into your Blackboard course.
This site allows you to search any word and see different meanings and associations with other words. This could be helpful for students when learning new vocabulary or even old vocabulary and discussing which meanings are applicable to your subject and what you are learning in the classroom.
This is a very interesting article about using technology to provide additional instruction as well as looking at possibly flipping the classroom structure. The article shares both pros and cons of Khan Academy and not associated with a school district.
This website has some games on it but what I really like is the seating chart, group generator, and random name generator. I used it for student teaching and it is easy to upload a class list (make sure to just use their last initial for safety purposes).
This is a Creative Commons Google slideshow that shares 34 interesting ways Twitter can be used in an educational setting. It is definitely worth a read - knowing if you pull one new thing out of here to use, you have already put a step closer to engaging your students in a new or different way! Why not try?