This has been a LIFE SAVER in my classroom on numerous occasions! Internet4Classrooms has the most user friendly database of online activities, tests, lesson plans, worksheets, etc. I've found on the internet.Any activity for grades PK through 8 can be located by a simple grade leveled search based on national education standards.
There are free tutorials that offer practical directions for educator related tasks using popular software programs.
This site also has examples of published standardized tests from several states to use when preparing students not to be "left behind'.