Regpack is an online payment software that allows businesses to collect and manage client data and payments from a secure back end dashboard. Email communication, integrated payments, recurring billing, reporting, and analytics are built-in. Regpack makes it easy to manage and charge clients securely with your team and embeds on your website for a seamless process.
Eventzilla - Eventzilla lets you sell tickets online and manage attendees from one integrated application.
Sitecake - Drag and drop CMS for HTML websites. It's flat file CMS so it's pretty fast.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Anchor CMS - Free and lightweight blogging system
Ticket Tailor - Ticket Tailor is an easy-to-use event ticketing platform that allows event organizers of all shapes and sizes to sell tickets online.
Textpattern - Textpattern is an elegant content management system that is free, open source software.