OSGeo Live

http://live.osgeo.org/

Short Description
OSGeo-Live is a self-contained bootable DVD, USB thumb drive or Virtual Machine based on Xubuntu, that allows you to try a wide variety of open source geospatial software without installing anything. It is composed entirely of free software, allowing it to be freely distributed, duplicated and passed around.

It provides pre-configured applications for a range of geospatial use cases, including storage, publishing, viewing, analysis and manipulation of data. It also contains sample datasets and documentation.