Dudle - Dudle is an online scheduling application, which is free and open source.
ResourceGuru - The fast, simple way to schedule people, equipment, and other resources online.
FullCalendar - FullCalendar is an open-source JavaScript event calendar.
Float - The leading resource management software for agencies, studios, and firms. With a simple, drag and drop interface and powerful editing tools, Float saves you time and keeps projects on track.
Framadate - Make your polls
When I Work - When I Work is an employee scheduling and communication app using the web, mobile apps, text messaging, social media, and email.