Loomio - Loomio helps groups of people make decisions together, online.
Meetingbird for Gmail - View your calendar and schedule meetings right from Gmail
DemocracyOS - DemocracyOS is an open source application for online decision making.
Kin Calendar - The simple and connected calendar
Airesis - A decision making tool for direct democracy and e-government: participate in discussions, bring your ideas, suggest solutions and vote online
Calendly for Chrome - Schedule meetings without leaving your inbox