Study Jam site is a great way to grab your kids attention with Math and Science. Some of the lessons have a video or Step by Step video showing how to solve something. Then the site has a Test yourself piece that you could have your kids write down their answers and discuss as a class. This would also make a center.
As you are preparing for a new lesson or topic, don't forget about Promethean Planet and Smart Exchange. These sites have interactive lessons ready for you to use. I know that we don't have Promethean or Smart Boards in the classroom, but you can use the lessons from your computer. These activities could be used with the Mobis to make your room interactive.
Northside purchased licensing from ASCAP to be able to play music in this repository for performances. If the song that you want to play in the repository, then we can legally play it for groups of people. The music isn't there, we still have to purchase the music, but this agreement allows us to play it for large groups of people like PTA or for morning announcements. Please check this site to ensure that we are following copy write laws with our music.