Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.
Framadate - Make your polls
NeedToMeet - Schedule a meeting in a few clicks to find a time that works for everyone.
Dudle - Dudle is an online scheduling application, which is free and open source.
YouCanBook.me - YouCanBook.me is a cloud-based service which allows your customers to schedule appointments and make bookings.
FullCalendar - FullCalendar is an open-source JavaScript event calendar.