OSGeo Live

OSGeo Live exists to solve a specific, real problem for geospatial researchers and students: dozens of powerful open-source GIS tools (QGIS, GRASS GIS, PostGIS, and many more) exist, but installing and correctly configuring even a handful of them together can take real effort, and OSGeo Live ships them all pre-installed, pre-configured, and cross-tested to work together. It's built on Xubuntu and distributed as a bootable live image, letting anyone try a full open-source geospatial software stack without installing anything, and each included project ships with its own quick-start guide as part of the OSGeo Live documentation. It's widely used in university GIS courses specifically because it removes the software-installation barrier from a first exposure to these tools.