We get WordPress by the open source community, and because it’s open source, we can do quite everything we want. So we would like to share back to the community some of our source code, hopefully useful to someone of you:

CSS:Greyscaper : greyscale WP Admin color scheme for WordPress 2.5+
» more info & download

Upload+ : rename and sanitize the file you upload according to your custom rules.
» more info » support forum (en) » download

Category Page: use a page content as a header for your category archives.
» more info » support forum (en) » download

ANT : news ticker widget with unobtrusive javascript. can display posts or RSS feeds.
» more info » support forum (en) » download