I'm talking about consciously choosing not to shower, not being stuck out in the woods on a boy scout trip or something. And no, golden showers don't count.
Mine was probably a week and a half. It was about 2 years ago and I had just moved and started a new job, so I was working a lot, moving, etc. and I just had more important things to do... so I just sucked it up for a little bit. I don't think I smelled THAT bad since no one said anything to me. When I finally got around to it, I gave myself the deluxe scrubdown treatment, using Comet and a plastic scrubbrush.
I did perform some "routine maintainance," cleaning some of the more private areas, since they tend to get stinky a little more easily. I also employed the "Puerto Rican shower" technique (no offense) by dousing myself with cologne. These are essential if you want to get the most out of not showering, while avoiding rashes and strange looks.