http://grano.la/ Thought it'd be worth checking out. Granola dynamically adjusts the power your computer uses so it draws only what it needs. You save almost 40% of CPU energy by just letting the damn thing run in the background! Your computer thus draws less energy, thus improving its friendliness towards the earth. It doesn't affect performance, either. On top of that, it tells you how much money, carbon, and power you've saved. And since it slows power consumption, it stands to reason that it would extend battery life on laptops. This is absolutely the case; people report an extra hour or so on their laptops. Did I mention that it's free? This is one of those things that you have no reason not to get.