Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform
attending.io - Tiny event pages to ask people one question – are you attending? Twitter login.
EventCreate - 100%-free event ticketing
pretix - pretix helps you to sell tickets for your event in an easy way. It supports multi-lingual events and provides a wide range of features
Picatic - Picatic encourages event organizers to create a custom website, sell tickets and then determined their cost of use. Selling out events is easy with Picatic.