Following the recent disaster in Japan, the Tokyo Hackerspace --an open community space where hackers get together to play with hardware (among other things)--channeled its hive mind not into its usual playing with lasers and forgetting to shower, but rather into helping the country recover from earthquake and nuclear-related woes.
The Tokyo Hackerspace's most high-profile project is its NETRAD geiger shield,  an open-source geiger counter shield that detects local radiation levels. Eventually, the hackerspace hopes to expand its sensor network to the Fukushima region. But the geiger counter project is just one of many community-oriented initiatives from the Tokyo Hackerspace. Other quake-related projects  include solar lanterns, personal disaster protection packs , and even geodesic dome kits .
The Japan disaster didn't somehow switch the Tokyo Hackerspace into this altruistic mode; it was already there. The group is also working "smart" canes for blind people, solar cell phone chargers, and a rice farm wireless sensor network.
Lest you think that the Japanese are alone in their community-mindedness, other hackerspaces around the world are helping out with the diaster relief---and working on similar projects of their own. Ohmspace in Oklahoma sold T-shirts and stickers to raise funds for the Tokyo Hackerspace's solar lanterns, and Arizona's Heatsync built 300 lanterns for the Tokyo group.
Washington, D.C.'s HacDC is working on its own disaster preparedness project, dubbed Project Byzantium . The project aims to develop a communication system for users to connect and share information in the absence of easy Internet access. Potential use scenarios include natural disasters, a government Internet shutdown (a la Egypt), or "a zombie apocalypse in which the personnel responsible for maintaining key infrastructure have all been turned." See, still nerds, just nerds with hearts of gold.
This isn't to say that hackerspaces don't work on superfluous projects as well; the Tokyo Hackerspace, for example, recently made LED clothing for dancers at a local Michael Jackson tribute concert. But when people with enough free time, knowledge, and good intentions gather together to tinker with gadgets, positive outcomes will often result.
[Photo Credit: John Kit ]