This is a fellow teacher's bog. She posts a lot of great sites that you can go to to find fun interactive games that students can do either on the SMARTboard, on individual computers, or in small groups!
It's cool that you can publish a mindmap that you make to your webpage-your students could make one and post them to your classroom website! I haven't tried it yet though. I'd watch the demo they offer through the help menu. It gave the basics. My only problem with it was that sometimes it would be slow and not do what I needed.
Free online graphic organizer that allows you to create webbing graphic organizers. You could use it to create a graphic organizer with a SMARTboard or have your students create their own.
All sorts of math, science, and lanuage arts activities that can be used on the smartboard. There are science activities for the food chain, health and growth, plants and animals and much more. 4th grade - there is a an activity for friction and forces in motion that made a great formative acitivity last year.