Peer to Peer Disaster Relief - someone needs what you have to give - make it happen on iCARE a project in progress from the engineering school at UC Berkeley.
Crowd-sourced product (or service or action) design. Kluster was recently used to design a social game that builds global cultural awareness.
A new app to organize social action on Facebook. Read about it here.
In what might be seen as a birth-child of Kluster and Ultimatums a recent Stanford class created 50+ Facebook apps in 10 weeks (100 students, 10 million installs, and 1 million daily users). They shared what they learned at the Graphing Social Patterns Conference.
Netsquared MashUp Challenge
Netsquared, a project of CompuMentor and TechSoup, is entering Year Three and has openings for a Google Hackathon (March 7, Mountain View, CA) and Mashup Challenge (Applications due March 14)
Goodwill Industries uses the web to sell its wares, train its employees, and help them build community - here's a video of Goodwill's CIO discussing the applications.