Bubbl.us is a free online tool that allows users to create mind maps for brainstorming ideas. It lets multiple people collaborate on mind maps simultaneously and embed maps into websites. While the interface is initially confusing, it becomes easy to use after exploring the options. Bubbl.us would be useful in classrooms for brainstorming ideas as a whole class or having students access teacher-created maps for reference. The document recommends it for 6th graders and says the author plans to incorporate it into their future lesson plans.