Calendarix - Calendarix is a powerful and easy to use web-based calendar that runs on PHP and MySQL.
DialogTech - DialogTech is an end-to-end call attribution and conversion platform.
Cronofy - Unified Calendar API for developers
CallTrackingMetrics - Know who is calling and how they found you. Maximize the return on your advertising.
ApPHP Calendar - ApPHP Calendar is a PHP calendar script that may be easily integrated and used with various PHP projects, such as schedulers, event, etc.
Marchex - Marchex is a mobile advertising analytics company that connects online behavior to real-world, offline actions.