Looking for Activities or Specific Resources - check below:

Simulations

PhET - This site has great simulations that could be used in the classroom

Curriculum Sites for Educators

Study Stack - This is a great site for getting flash cards and other resources for many subjects.

TeachersFirst.com - Content Matrix - This is a good place to begin searching for activities by subject or grade level.

Discovery Education - This site has great teacher resources - from quizzes online, puzzlemaker to a lesson plan library.  Spend some time with this site!

ReadWriteThink This site has professional development, student and parent resources and classroom resources.

Teach-nology - Free and easy to use resources for teachers dedicated to improving the education of today's generation of students

PBS - Search by subject and grade level through hundreds of lesson plans with supporting material.

BBC - Resources for grades K-12 across all disciplines.  Very interactive.

Activities

ABC Teach - Includes over 5000 free printable activities including flashcards, worksheets, some activities are for members only.

A to Z Teacher Stuff - Another site with many activities and resources for teachers.

Jeopardy Labs  - This site will generate Jeopardy games for classrooms.

Puzzles

Puzzlemaker - Allows you to create different types of puzzles from Discovery School.

Bingo Cards

Bingo Card Generator - Make your own bingo cards.

Rubrics 

RubiStar - RubiStar is a free creating tool to help a teacher make quality rubrics.

Webquests

Webquests - Resources for building webquests.

Wordcloud Generators

Wordle  - Easy to use word cloud generator - fun!

Imagechef  - Puts word cloud in a shape.

Storyboards

Glogster  - This site is great for a class that will be doing class presentations.

Presentations
 Prezi – this is a new way to do a presentation – this is a little trickier to use but a cool way to liven up a powerpoint
Dictionary
 Viziwords – this is an online graphical dictionary – see words in a whole new way!
 
Pictures 
Flicker - one of many photo websites

Spelling Lists

Spelling City – the students can put in their spelling words and can practice seeing and hearing them and from there, make games using the specific words.

Bookmarking Sites

Diigo - This site is a bookmarking site but also can be used for group work and highlighting sites.

Screencasting: making video recording what is on the computer screen

Screencastomatic - pretty easy to use - will need a microphone for your computer.

 Blogs and Wikis

Blogger - Google's free blog tool.  Students register with an e-mail address and then get their own URL for blogging

WEB 2.0

Animoto - Automatically converts a series of images to a music video

Voicethread - add narration to still images - allows for collaborative use where every student can add his or her voice to a picture- can upload voice from computer or phone

Bubble.us - online "Inspiration" - no need for software - control content, color, spacing and more right from your web browser

Audacity - Free audio recorder and editor - can be used to create podcasts