Wikispaces - Wikis for Everyone
Wikispaces is a is a free wiki host. Registered members can create new spaces (e.g. spacename.wikispaces.com) that are public or private wikis. We're all about ease of use - teachers, students, clubs, churches, and social groups all call Wikispaces home. There are virtually no limits on the number of members, pages, and files you can host in your wiki.
Sparkline PHP Graphing Library
Sparkline is a PHP graphing library purpose-built to generate "intense, simple, wordlike graphics". Sparklines are the brainchild of Edward Tufte. See also Sparkline's freshmeat listing and a more thorough explanation of sparklines.
Scry: Simple PHP Photo Album
Scry is a simple, secure, fast, and free photo album for your website based on PHP 4 and GD. Scry doesn't use a relational database and has no administrative or user front end. Change your image files and directories and your albums will change automatically. Image resizing and caching is done on the fly for speed. You can easily embed Scry into an existing site via XHTML templates. Scry is stable, secure, production-tested and openly distributed under the BSD licence. See also Scry's freshmeat listing.