Way back in 2008 I blogged on Open Source Ecology (OSE) which is an open source project to create tools and knowledge to build a fully sustainable village. The project has grown since then and they are going even further by designing tools that can be fabricated on site. Recently, they made a good video explaining more about what OSE is all about.
The One Laptop Per Child (OLPC) project aims to bridge the digital divide by providing relatively inexpensive computers to kids in the developing world. The cost of the machine has unfortunately increased from their proposed $100 USD to almost double that, in oprder to ensure that they can still get these laptops out to the kids they are selling them as pairs.