If you are a proud fellow-owner of a MacBook you probably like it as much as me. And since you like it that much you want to keep it in good shape for as long as possible, right? Well here I got one for you: Calibrating the battery will help to increase its lifetime.

Here's how:

1. Charge Battery fully (green MagSafe light) and keep the cable plugged for some 2 hours.
2. Disconnect MagSafe and wait for battery to discharge itself so much that MacBook goes to sleep.
3. Let MacBook be for at least 5 hours straight.
4. Charge Battery fully again.

From what I gathered you should do this about once a month for full effect.

Calibrating your computer's battery for best performance