CKEditor - Real-time collaborative future-ready rich text editor
Loxi - Easily add an events calendar to any website.
TinyMCE - TinyMCE is a content editor that functions as a plug-in for Wordpress websites.
Whenever - Casual calendar app for iOS
Trumbowyg - Feature-packed WYSIWYG editor in only 15kB of JavaScript
Future - Calendar events around the clock