I created a page of little stars falling from the top of the page.
Animation: Although animation is "cool" you need to keep in mind not to let it distract viewers from the goal of your website. Animations slow your pages down, so use them sparingly yet in a way to "wow" your audience. I use Flash5, Director, DHTML, and Ulead GIF Animator.
JavaScript: More for functions like detecting the user's browser (to match your Cascading Style Sheets), or for verifying the fields in a form have been filled out, or to add a nice rollover effect on the buttons of your navigation bar.
Java: Warning! These applets do increase download time. When necessary though, they can deliver awesome visual effects.
CSS: Mainly for making all your pages look the same in formating structure. Advanced features of CSS include animation of words flying in as well as animating ordinary hyperlinks