I think most of these are totally staged. That is the prank-ee is in on the joke. Otherwise, the prankster could be charged with assault. In one real prank the prankster was shot.
ON POSTING YOUTUBE. All you have to do is put the YouTube code between the tags. In the first example only the "aUwgfiFDuMA" has to be put between the [you tube] and the [/youtube] . So it would look like this: NOTE EXTRA SPACE in YouTube was put to prevent the tags from actually working so you could see it.
[you tube] aUwgfiFDuMA [/youtube]
So the result is, once I take out the extra space: