Calagator - Event aggregator. (源码) MIT，Ruby

Clerk - Simple event logger to keep track of periodic events, habits, etc. as they occur. GPL-3.0，PHP

dudle - Online scheduling application. (演示, 源码) AGPL-3.0，Ruby

Feedka⚠ - Open-source web application that can serve as a platform to get authentic, kindful, and constructive feedback from your friends, family, and co-workers. (演示) AGPL-3.0，Ruby

Fider - Open source alternative to UserVoice for customer feedback. (演示, 源码) MIT，Go

Framadate - Online service for planning an appointment or make a decision quickly and easily: Make a poll, Define dates or subjects to choose, Send the poll link to your friends or colleagues, Discuss and make a decision. (演示, 源码) CECILL-B，PHP

hitobito - A web application to manage complex group hierarchies with members, events and a lot more. (演示, 源码) AGPL-3.0，Ruby

JD Esurvey - Open source enterprise survey web application. (源码) AGPL-3.0，Java

Kyélà - Participation polls for group events. (演示, 源码) AGPL-3.0，PHP

LimeSurvey - Feature-rich Open Source web based polling software. Supports extensive survey logic. (演示, 源码) GPL-2.0，PHP

Meetable - Event aggregator. (演示, 源码) MIT，PHP

Open Event Server - Enables organizers to manage events from concerts to conferences and meet-ups. GPL-3.0，Python

PHPBack - The open source feedback system. (演示, 源码) GPL-3.0，PHP