Cvent - Cvent's event management software provides event planners with a complete solution to increase event attendance and decrease event costs.
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
EventMobi - EventMobi is an interactive mobile event app, audience response and engagement platform for conferences and trade shows.
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
EssentialPIM - EssentialPIM is a free Personal Information Manager that keeps up with the times and lets you manage appointments, tasks, notes, contacts, password entries and email messages across multiple devices and cloud applications.