After 6 years of stellar service, the MacBook got extremely noisy, due to the internal fan going off-kilter—loud enough to eclipse the whirr of a CD spinning in the drive.
Thanks to iFixit's very thorough, clearly documented, and well-photographed fixit guide, I was able to methodically go through removing screws, plates, etc. to get to the meat of the MacBook. A couple stubborn screws here and there, but for the most part, a very interesting tour through the innards of a laptop computer. And I got the fan replaced and the quietness of my laptop back in the end!
TIP: get a few 8.5 x 11 blank paper sheets, a pen, and some transparent tape. As you go through each step in the process, mark down the step #s and attach the removed screws/parts with pieces of transparent tape under the written step #s as you take them out. That way you know which parts correspond to which step as you reassemble the laptop back up. Also, be sure to write down the screw lengths under the screws as you attach them to the papers so you won't end up putting the wrong screws in the wrong holes (or have to measure them with a tiny ruler to find their lengths).