CalDavZAP is a CalDAV Web client with a powerful event/todo editor. It is compatible with Safari, Webkit, Firefox, Opera (15+), iCab, and Chrome, and supports all major CalDAV servers.
CardDavMATE is a CardDAV Web client with a powerful vCard editor. It is compatible with Safari/Mobile Safari, Webkit, Epiphany, iCab, Chrome, Firefox, and IE9, and supports all major CardDAV servers.
A PHP script to build your own classifieds site.
An implementation of a cryptographic store accessible through PKCS#11.