Two three days before when I entered to http://plugins.jquery.com I thought it might be a small error and will be fixed in a hour or so. But, when I returned it showed the same message COME BACK LATER.
But today when I opened the same URL I found the message displaying The plugins site is currently in development.
So the real Question is What happened to plugins site?
The site Administrators were making sure that spam aren't there, by deleting them.
But, accidently all the plugins were deleted.
And adding to it they dosen't had a backup. The only backup available was a year old.
And jQuery team is planning a new site.
*Also hats of to them about their for their honest explanation. *
You can try this http://wayback.archive.org/web/*/http://plugins.jquery.com/ for the previous preview.