makeplans.netSoftware by MakePlans
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.
Appointment Booking Calendar - With the Appointment Booking Calendar you can accept online bookings from a set of available time-slots in the calendar.
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.
Dudle - Dudle is an online scheduling application, which is free and open source.