Scholastic

http://www.scholastic.com/magicschoolbus/
This site is full of activities that teach and demonstrate science concepts. There are instructions for experiments, games that test your knowledge about weather, the human body, insects, and more. There are also clips of certain episodes of The Magic School Bus TV show. I would use this site to help kids to learn basic science concepts. I would love it if a computer specialist would let my students investigate the site for a few computer class times. I'd also use it as a center in my classroom.
http://www.scholastic.com/kids/weather/
This site lets you adjust the polar temperature, equator temperature, and the humididty and has an animated picture that shows what effect the different temperatures and humidity have on weather. It would be a great site to use if teaching a lesson on the poles, equator and/or humidity. It wouldn't take very long to investigate the site, so maybe I'd have it available throughout the day for a couple of days for students to look at and play with during any free time.
http://www.scholastic.com/kids/president/
This site makes you the president, has you pick advisors, justify who you picked, and balance the national budget. It's much, much simpler than real life, but it would give students a chance to think about the responsibilities of our country's president and evaluate what they think is most important. After picking and justifying advisors and balancing the budget, a newspaper page comes up with an analysis of what you've done. In my class, I would take my students to the computer lab abd have each of them complete this activity and print off their newspaper page. We would then discuss why people made the decisions they did.