Wren - Offset your carbon footprint by saving rainforests
Website Carbon Calculator - Find out the how much CO2 your website emits
Neutral - Offset your carbon emissions, right from your shopping cart
Treeapp - Plant a tree for free, every day, in less than a minute
Trip to Carbon - A carbon footprint calculation API for travel.
Capture - A great free screen capture utility that allows you to capture either a window or the desktop and save it to either a file or the clipboard.