Cvent - Cvent's event management software provides event planners with a complete solution to increase event attendance and decrease event costs.
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
EventMobi - EventMobi is an interactive mobile event app, audience response and engagement platform for conferences and trade shows.
Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Strikethru - Strikethru is a kind of to-do list notebook for managing work lists and staying updated with the important tasks.