There is no better way of learning about circuits than to get out the wires and play. But this is a good resource that helps you teach about circuits and how to build them. Good as an introduction to the topic.
http://ictmagic.wikispaces.com/Science
A good sport themed maths basic operations resource. Answer questions about + - x ÷ to make your swimmer faster to win the race.
http://ictmagic.wikispaces.com/Maths