Last week I downloaded and setup MediaWiki on my local development machine. As the MediaWiki site will tell you it runs using PHP extensions for IIS and is powered by MySQL database - both tools that can run along side my .NET development environment without causing conflict. My original reason for downloading and installing it was to evaluate how hard it would be to deploy / adapt for one of our clients that might require a Wiki site later in the year. I have, however, found having a Wiki running locally to be a valuable tool while I develop.
One of the core challenges of software development has always been keeping useful and current documentation. It always seems to be one of the first parts of a project that is dropped when a deadline gets tight, if was even included in the first place. With the Wiki running, I can keep it open as I write code so that I can add to my high level documentation as I'm going. Writing documentation as you go is bound to make it more accurate and useful to other developers that might have to pick up your work.
My advice... throw away all those scraps of paper on your desk, and even that notebook (if its like mine it hasn't been touched for a few weeks anyway - who uses pens these days?) .. And install MediaWiki today!