Put your laptop charger (and other chargers) on a timer.

Around our house, you can find a handful of outlet timers that serve one purpose and one purpose alone – to make sure devices come on for only a portion of the day when they’re needed.
For me, I tend to use my laptop about once a week. The rest of the time, I usually leave it on the charger and forget about it, but that presents two separate problems. First, leaving it on the charger degrades the battery over time. Second, leaving the charger plugged into the wall – with that big old converter box on it – eats energy at a pretty rapid rate. It eats about 50 watts per hour, according to my measurements.
Thus, I just leave the laptop plugged into the charger all the time when not in use, but the charger is plugged into an outlet timer. That outlet timer comes on from midnight until two in the morning, just long enough to make sure the laptop refuels. If I need it on during the day for some reason, I just reach over to the outlet and touch a button – it then stays on until two in the morning and returns to that cycle.
That outlet timer is saving me a lot of money. I estimate that on an average day, it eliminates 15 hours of energy use by that charger, as I just tend to leave my chargers on the outlet for my convenience. At 50 watts, that adds up to a savings of 273.75 kilowatt hours per year, an annual cash savings of $27.38.