Create a mindmap.
Bubbl.us - Create and edit mindmaps effortlessly. Using the drag-and-drop interface, students will be creating beautiful mind-maps in seconds!
Edistorm - A site for real-time brainstorming. Organize your ideas on an interactive wall, complete with colored sticky notes. Some features available only with educational and/or premium accounts. Educational discounts available for premium accounts.
FreeMind - a free downloadable mindmapping editor with extensive features.
Glinkr - Use this tool to link ideas with expandable details and URLs. Mindmaps can be made public and then embedded on webpages. The free registrations also allows printing and saving of mindmaps.
Mindmup - Create awesome mindmaps with this '"zero-friction" free web-based tool that can be made either private (through Google Drive), public or private off-line. Tons of features including some optional extensions which allow for collaboration, progress-tracking (for task-based maps), DropBox integration, and more.