I have a variety of flash memory devices. I picked a two-Gigabyte device to put a copy of MediaWiki and SVN. I now can access my personal wiki everywhere I go.
Wiki on a Stick
CH Software created MoWeS, an entire WAMP (Windows, Apache, MySQL, and PHP) stack that run without the need to install anything. MoWeS allow selecting which version of Apache, PHP, and MySQL. MediaWiki is an additional option along with other great options like ImageMagick, TYPO3, and SugarCRM. MediaWiki provides an installation page. The instructions are not quite right. Download the packages from CH Software then run moves.exe. That unpacks the files.
SVN on a Stick
I use TortoiseSVN. This integrates SVN with Windows Explorer. TortoiseSVN has the option to create a repository by just right clicking on a directory. This makes it simple to create an SVN repository on a memory stick.
Performance of SVN is a slow on my two-Gigabyte flash drive. The advantage of taking both my personal wiki and an SVN repository with me anywhere outweighs the performance issues.