Time Slot Booking Calendar PHP - Time Slots Booking Calendar PHP for online appointment booking and class scheduling.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Pulse 24/7 - Booking & scheduling mobile app for service providers
Cvent - Cvent's event management software provides event planners with a complete solution to increase event attendance and decrease event costs.
Dudle - Dudle is an online scheduling application, which is free and open source.
Ticket Tailor - Ticket Tailor is an easy-to-use event ticketing platform that allows event organizers of all shapes and sizes to sell tickets online.