PHP & MySQL Search Engine/Site Index:
php3 file
MySQL Database for search engine
A very extensive script I recently wrote when I decided to do a complete renovation of my search engine.  The script combines the Yahoo style index  on my IIS home page with a powerful, case-insensitve keyword search.  The script uses wildcards to find related matches, the DISTINCT attribute in SQL to eliminate duplicate matches, controls the number of matches shown per page, handles the "no results found" instances (of course), and provides a miniature link next to every match, leading to more content relevant to the search query that can be found in the Yahoo-style index. I could have done some Regex/Ereg coding to handle key phrases; however, since I don't have that many urls (compared to, say...microsoft), I didn't see the need to provide support for key phrase or Boolean AND/OR searches.  Most of my main pages are very short, so keywords are more effective than key phrases for my particular situation (I tested this theory).

Server-side Includes (SSI): 
Header-php3 file
Side-Bar -php3 file
Search page (uses includes) -php3 file
I use server-side includes to make changes to the format of my IIS pages much easier...changes to headers, side-bars, etc.  However, these SSI's have a twist to them:  The color schemes of my sites change 3 times a day (to prevent boredom) - Turquoise in the morning, Purple in the afternoon, and Blue at night.  In addition, the font on the header changes twice a day, while the greeting changes 3 times a day to reflect the time of day.  The sidebar contains images made on the fly using GD & Freetype, including the dynamic analog clock described in the next paragraph. (On my site, the clock also changes colors to match the scheme...the one below doesn't).  The content of the sidebar also changes based on the time of day.  In the morning, useful links to news & weather are displayed.  At night, links to programming resources are displayed (appropriate for me), etc.  Here are some screen shots of my SSI's in action:
IIS-Morning 
IIS-Afternoon
IIS-Night
Sidebar-dynamic content

PHP/MySQL - Yahoo-style index:
I've been using MySQL to (among other things) create a Yahoo-style index of all my sites on the home page of my IIS server.  This is the script for accessing the database and printing out the results: 

 php3 file

abbreviated dump file for the DB
Snapshot of Yahoo-style index:

Analog Clock:
php3 file
(My latest mini script. I got tired of those boring digital clocks, or worse yet, those scripts that just print the time. So, I figured a nice analog clock with hands would be a classy change of pace. It's a dynamic image created completely using PHP (no image editors and no images saved on the server). The time is updated everytime a page is loaded. I use this on the sidebar of my site on my IIS server. An easy little script I threw together after Thanksgiving dinner.)  Here's a screen shot of the clock:
Sidebar-Analog Clock

Bar Graph:  php3 file
(Allows the user to create bar graphs with their own numbers, titles, and names. They can even choose a color scheme.  To get an idea, check out the Javascript version.  Also scripted in ASP , Perl, Python , and JSP)

Crossword Puzzle:  php3 file