In fact, it's worth calling attention to Microsoft's active open-source involvement simply because so few imagined that Microsoft would ever show up at the party. Among the successes is IronPython, a Python implementation designed to run on .Net and Mono; Version 2 was released in February. Now that that's done, the team can turn its attention to an IronPython version to support Python 3.0. While the team is vague about a release date ("after 2.x is out the door," according to a spokesperson), it will likely arrive sometime this year.
Microsoft also created IronRuby, a Ruby implementation for .Net, and the Dynamic Language Runtime, a set of shared services for implementing dynamic languages on .Net. All three projects are distributed under the terms of the Microsoft Public License.
Also worth watching:
The MariaDB project, a community-developed branch of the MySQL database using the Maria storage engine; the brainchild of Michael "Monty" Widenius, founder of MySQL AB and Monty Program AB.
CodeIgniter 2.0, a PHP framework with a very small footprint, built for PHP coders who need a simple and elegant tool kit to create full-featured Web applications. (While Version 2.0 hasn't exactly been announced, you can pre-order a book about it on Amazon. Hmmm.)
Eclipse Galileo, a coordinated release of different Eclipse projects, due to ship at the end of June 2009.
Most of the preceding projects are of interest mainly to geeks (and we mean that in a nice way). Increasingly, though, businesses are adopting open-source software for productivity use and line-of-business applications.
Primary among these is the open-source "replacement" for Microsoft Office. OpenOffice.org 3.1, expected imminently, is currently available as a "developer snapshot." It promises grammar checking, anti-aliased drawings, improved charting and better outline features.
That's on top of the new features from Version 3.0 (released in October 2008), including compatibility with ODF 1.2 and OOXML and native Mac OS X support.