Nuages - Nuages is a collaborative meeting poll system..
FullCalendar - FullCalendar is an open-source JavaScript event calendar.
Framadate - Make your polls
Letsfind - Letsfind is a fast, easy-to-use, ad-free way to create online (meeting) polls.
CozyCal - Online appointment scheduling
Dudle - Dudle is an online scheduling application, which is free and open source.