The StixFonts project is a project to produce high quality fonts for academic publications.
It has been in progress for over ten years and there has been a beta about two years and a half ago. At the same time there had been a discussion on the relevant license for these fonts. The first draft of the license would have made the fonts obsolete as soon as they would be released. However, after public consultation, the project selected to use the Open Font License (OFL).
StixFonts support mathematical symbols from Plane 1, however the WordPress post editor is not able to handle them and truncates the post when you save :-(.
Apart from mathematical characters, StixFonts support Latin, Greek and Cyrillic. Compared with DejaVu (default font in Ubuntu), DejaVu still has overall bigger coverage. You would want to use StixFonts if you write academic documents and require to use a wide range of math symbols.
You can get the StixFonts from the StixFonts project website, at version 1.0, in OpenType format. From the zip archive with the fonts, extract the *.otf files into your home directory, in a subfolder called .fonts (if it does not exist, create it). No need to restart the system; any newly restarted applications should be able to see and use the fonts. OpenOffice.org 3.2+ is required (for example, in Ubuntu 10.04) due to the OpenType format of the fonts. If you use OpenOffice.org for your document writing, it might be a good idea to create special styles for your math content and set the StixFonts as the font of those styles. You can type in those math characters using Insert → Special Character… in OpenOffice.org as shown below.
These are the mathematical alphanumeric symbols (fraktur style) in Plane 1. You may notice that some characters are missing (such as capital N fraktur style). It’s not a bug. In OpenOffice.org, you click on characters and these are added in a string. Then, when you completed the string with all the special characters you click OK and they are inserted in your document. While we wrote ubuntu as sample text, these are symbols meant for math documents. However, the potential for geekiness in the Facebooks and the Twitters is easy to describe.
The beta version of the StixFonts are already packaged in Debian/Ubuntu as ‘otf-stix’. I suppose the package will be updated soon with the new version 1.0.