|Below are a number of sites that offer pre-made (as opposed to user generated) content in a variety of subject areas. You can link to or embed most of the content on these sites with just a couple clicks.|
SlideShare.net - Upload your own or search for 1000s of PowerPoints on any subject that you can easily embed on your own site.
Prezi search - Find other Prezi's that people have shared publicly.
Pete's PowerPoint Station - The site looks old school, but has tons of great stuff for every topic from elementary through high school level.
Thinglink - Add hot-clickable buttons to your photos to make them interactive.
Popplet - Sort of a simplified version of Prezi. It's also works nicely with google maps and allows you to draw things within a presentation.
Video sites (beyond YouTube)
Snag Films Education - Features educationally themed documentaries in a variety of subject areas.
Khan Academy - A how to video for just about any concept you can imagine. Everything from elementary math to sequencing DNA.
Brain Pop - This is a pay site, but you can get a free trial if you're in a pinch. Also, some movies are free anyway. All subject areas - very well done.
Tube Chop - Watch just the part of a movie you want. Edit the start or end times to see just what you want.
The Mad Video - Kind of like Thinglink for videos
Explania - Very nice interactives for a variety of science and social science conepts
Nobel Prize Games - Outstanding interactives on topics that won the Nobel Prize.
Interactive Whiteboard Site** - A huge repository of interactives in all subject areas. Especially helpful for elementary. The activities can be completed without an iboard.