Click each link below to view a text file of the script described. I'm not really good at writing Javascript and DHTML yet so some of these I copied off of other sites. Further comments will be given within the text.

HoverColor - Style sheet. Changes color of links to another color (red in this case) when the pointer moves over the link.
Ghosts - Three images follow your mouse around on the screen. Pretty complex script. But that's just me.
BrowserDetect - Two browser detection/redirection scripts. Simple and effective.
Pop - A simple pop up script. The window it opens is small and clean. Helps you avoid the target=_new.
Ticker - This script's pretty long, but it replaces memory hogging Java applets that do the same thing.
FloatingImage - Only works with Internet Explorer :-( Floats an image across the screen in random directions.
Animate - Floats an image around your browser window while centering it at the samet time. You also need Animate.js. Hold shift and click.
CrazyLines - This script/css is HUGE. Draws 4 lines (2 vert and 2 horiz) and moves them across your screen. You need CSScriptLib.js.
Transition - Does this nice transition from either when a user leaves or enters the page. IE only.