Mixmax Calendar - The fastest way to schedule meetings with anyone, anywhere
Clockwise - Time & attendance tracking with QuickBooks integration
Calendly for Chrome - Schedule meetings without leaving your inbox
Schedulr - Schedulr makes it easy to meet with others w/out the headache of back-and-forth emailing.
Polymail Calendar - Schedule meetings instantly over email
Teamup Calendar - Cloud-based calendaring using capability URL, application developed in Zurich, Switzerland.