There is a natural fit between university students and researchers and the open source community. They are smart, educated, short of cash, and want to make the world a better place; and some of them, at least, have plenty of spare time.
More seriously, open source projects are a great platform for software research. By starting with a mature software platform, the researchers can spend less time recreating existing functionality, and get to the new, interesting stuff faster. The findings of such projects are more applicable to the real world because the new ideas have been tested in realistic architectures and on data sets of a reasonable size. In the area of spatial (GIS) applications alone, there are several projects, including the work of Joel da Silva and others at Pernambuco, Brazil, the GeWOlap project, and GeoMondrian.
Still, the majority of the mondrian and Pentaho communities are from industry. I would love to get more committers and active community members from academia.
Open Source Boot Camp (OSBOOTCAMP) is a mini-conference which is trying to put that right. I will be participating in a panel on open-source database development at Berkeley this Thursday 30th October, along with open-source advocates Bill Maimone (Ingres), Josh Berkus (PostgreSQL), Mark Atwood (MySQL) and John Sichi (LucidDB).