Just about the only place you're going to find free video is through the viewfinder of your camera. There are many sources of clips and stock footage. However I don't think you'll have any luck finding what you're describing without payin for it... that's why most of us are here.
It would be nice to share clips on a royalty free basis amongst users. I'm sure someone would love to host it if it wouldn't consume such an overwhelming amount of bandwidth. But, in order to get any type of quality that we would want, it would be just too big.
I have few clips what I would not mind to share or just give away, but how I would do that?. I moved to different location and have a dial-up only.Most of those clips are in avi format (from 600mb to 1.6gig).
I found that the best way is do make your own.That way no one will claim rights to it.