Dudle - Dudle is an online scheduling application, which is free and open source.
Cortico.ca - Cortico is a medical clinic booking system integrated with OSCAR
FullCalendar - FullCalendar is an open-source JavaScript event calendar.
Framadate - Make your polls
skedge.me - Online Appointment Scheduling Customized for Enterprise Brands
Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.