This week's book giveaway is in the General Computing forum. We're giving away four copies of Arduino in Action and have Martin Evans, Joshua Noble, and Jordan Hochenbaum on-line! See this thread for details.
#11: Use oscillating fans, pointed at the people. A fan without a person is almost always a waste of power
This one really resonates for me. My "air conditioner" is two giant fans. One in each room. The room I'm in is the one that is on unless I have company. The living room has a four foot tall oscillating fan that I can't turn on high because it is too cold. The bedroom is a three foot fan that blows on the length of my body in bad. (I like it better than an oscillating one when trying to fall asleep.) Same thing about not being able to put it on high. I was planning to buy an air conditioner "when I needed it" - hasn't happened yet.