Sudoku! is a simple sudoku game written in Objective-C using the GNUStep 
libraries.

If you are using the libgnustep-art gui back and are getting errors 
like these...

2010-12-29 13:26:34.672 Gorm[3580] The font specified for NSFont, FreeSans, can't be found.
2010-12-29 13:26:34.672 Gorm[3580] Font not found FreeSans
2010-12-29 13:26:34.672 Gorm[3580] Font not found Helvetica
2010-12-29 13:26:34.672 Gorm[3580] Font not found Helvetica
2010-12-29 13:26:34.672 Gorm[3580] Font not found Courier
2010-12-29 13:26:34.672 Gorm[3580] Font not found Fixed
2010-12-29 13:26:34.672 Gorm[3580] Font not found FreeSans
2010-12-29 13:26:34.672 Gorm[3580] The font specified ...

you have to create some .nfonts for GNUstep. In the ubuntu software repos, 
there's a tool named mknfonts.tool which reads .ttf font files (among others) 
and turns them into .nfont files. To make your .nfonts, do something like...

      ## Make the fonts and leave them in the Fonts directory
      cd /usr/share/GNUstep/Fonts
      mknfonts /usr/share/fonts/truetype/freefont/*

      ## Set the defaults for NSFont to something other than Helvetica
      defaults write NSGlobalDomain NSFont <font name>

Since FreeSans was one of the fonts mknfonts generated on my system, I ran...

      defaults write NSGlobalDomain NSFont FreeSans