Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.
JQWidgets - Unique toolkit for HTML5 Web development
PHP Event Calendar - PHP event calendar script with multiple views and many customizing options.
Kendo UI - Fast, light, complete: 70+ jQuery-based UI widgets in one powerful toolset
The Receptionist - The Receptionost is a visitor managemnt solution that has visitor logging system to track visitor traffic.
w2ui - W2UI is a small JavaScript UI library with a complete set of widgets: layout, grid, sidebar, toolbar, tabs, fields, popup, utilities.