Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.
Queue-it - Queue-it empowers organizations to deliver seamless user experiences and protect their brand reputation by controlling online traffic.
PHP Event Calendar - PHP event calendar script with multiple views and many customizing options.
Qminder - Qminder works the way it sounds: It helps a company mind its queues.
The Receptionist - The Receptionost is a visitor managemnt solution that has visitor logging system to track visitor traffic.
ezTurns - Queue management system for retail stores, medical clinics, pharmacies, barber shops and many others