Cronofy - Unified Calendar API for developers
Dudle - Dudle is an online scheduling application, which is free and open source.
Calendarix - Calendarix is a powerful and easy to use web-based calendar that runs on PHP and MySQL.
FullCalendar - FullCalendar is an open-source JavaScript event calendar.
Campaign Calendar - Campaign Calendar by Bracket Labs builds a marketing calendar from your Salesforce Campaigns.
Smart Scheduling - Free scheduling software for spas, hair & beauty salons. Best online booking & calendar app. 100% FREE salon software. Try it Now!