Rallly allows you to save time in the scheduling process of meetings and events. It is open source and also offers a hosted version.

The Product

Rallly allows you to create polls and invite participants to vote on the best time for a meeting or event. After people voted on the best time, the organizer can select the time that works best for everyone.

Rally is open source and can be self-hosted or used as a hosted service. The hosted version is free to use and offers additional features such as email notifications and reminders. They offer an official Docker image to make hosting easy.