The <video> Tag in HTML 5
There are also web sites that will automatically generate the code for HTML 5 video, such as Vyd.com's HTML 5 video URL shortener.
Slow motion video of particles being impacted by a solid sphere
500 fps high speed video from NASA JPL
This is an actual working example of the <video> tag example code below. (Do View Source to verify that this page is using the HTML 5 DOCTYPE. You can also verify it is Valid HTML 5 using the HTML Validator. Try using it to validate URLs with HTML examples from other places that claim to be HTML 5 web sites!)