My brother Mark (pictured modeling t-shirt) invited me to Vermont Law School to speak at their Solutions Conference. He also works with the Vermont Environmental Law Society, which is running a cool fundraiser, selling t-shirts to purchase tradeable SO2 credits -- and then retiring these pollution credits from the market.
This (Craigslist housing ads plotted on a Google map) is what open APIs were made for. The locator balloon shows details, and even apartment pictures. Via BoingBoing.