Here is a Feed of the most popular scripts at Java-Scripts.Net:
Websites are no longer "advertising brochures" - we have left that phase far behind us.
Today's websites must more and more reach out to the viewer and offer increasing options, increasing opportunities to interact with the medium, by leaving comments, filling out forms, joining membership sites, interacting in Forums, playing games, creating blogs, RSS - all of these are ways of using technology to broadcast information.
Further than that, movement has become important - sometimes for its own sake, sometimes to emphasize or underline action on the site - but also for a purpose, to increase impact and communication, like the new technology that allows us to listen to audio and video messages online.
Scripts are the secret behind all this interactivity. Scripts changed passive websites into active websites. It is scripting that drives the net, that allows us to do the things we often take for granted. Today even the simplest site can be jazzed up by some scripting that will bring the site alive and allow the visitor to feel there is something there to investigate.