Most of the items on this page are very old, but still useful. Like most of the things on this planet, there are bits an pieces from other people's ideas and work. If anything on this page looks like something you wrote, please let me know. It's been so long I have no idea who to attribute.
I have some newer ideas, but most are a little complex for a space like this.
This is from about 1997. It's still the most simple image mouseover I've ever found. To use, you can name it something else, just change all three instances of "huh" and the source of the two images.
I use this to display all the images in a directory and make them a link to a larger image, with the same name in a directory called "big". This is used here.
A simple directory listing. This is also used here.
It doesn't do nice easing or anything, but it works for showing and hiding elements well. Used in navigation here.