SCC+Academy

I would like to learn about sites that I can use in my classroom for resources, games and activities. I have a laptop, internet access, and an LCD projector. This gives me a lot of options, but I need some direction and the ability to know what would just be wasting my time.

I would probably be most likely to use the google videos and images for use in power points.

I would like to know how to quickly turn off my laptop's feed to the LCD projector just in case something undesirable pops up and I need to shield it immediately. Someone told me there was a way, but didn't give me specifics.