attending.io - Tiny event pages to ask people one question – are you attending? Twitter login.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Ticket Tailor - Ticket Tailor is an easy to use event ticketing platform that puts you in control.
Cvent - Cvent's event management software provides event planners with a complete solution to increase event attendance and decrease event costs.
EventNut - Build compelling branded event sites with payment processing
Eventzilla - Eventzilla lets you sell tickets online and manage attendees from one integrated application.