What are those video loop things of like a city and cars driving and everything in fast motion?

What are those video loop things of like a city and cars driving and everything in fast motion? Some people have them on their myspaces. If anybody knows what they are called and/or a website i can find them that would be greatly appreciated. What are those video loop things of like a city and cars driving and everything in fast motion?Don't be silly. Ask them :)