Mightybell is an interesting service that combines elements of two things that many teachers love; calendars and Pinterest-like visual bookmarking.
On Mightybell you can create private and public groups based around any topic, interest, or event. Your group works together on a shared board. To that board you can add files, videos, pictures, text notes, post questions, and post events using the event calendar. To enable real-time collaboration Mightybell provides a chat function for your groups too. The Mightybell browser bookmarklet makes it easy to add any web content to your Mightybell group boards.
Mightybell from Mightybell on Vimeo.
Applications for Education
One way that teachers might use Mightybell is to organize resources for units they're planning to teach together. To do this teachers would create a private Mightybell group, pin notes and resources to it, and use the event calendar pins to plan the days on which they're going to use their shared resources.