Hi!
I did a blog post about Purity and explained that what Purity needed the most was maps. ( http://freegamer.blogspot.com/2011/02/purity.html )
So, in order to set an example I did a few maps and wanted to share them, and to explain how to do your own maps.
Mapping for Purity requires netradiant, a gtkradiant fork. I installed it with the aur package on my archlinux, it works well.
Once you have netradiant and purity installed, you needed to copy two things from purity to net radiant :
cp PURITY_FOLDER/content/radiant/purity.game NETRADIANT_FOLDER/
cp PURITY_FOLDER/content/radiant/games/purity.game NETRADIANT_FOLDER/games/
For instance, if you use ArchLinux and installed purity and netradiant from aur, PURITY_FOLDER is /opt/purity/ and NETRADIANT_FOLDER is /opt/netradiant/
Then you need to edit NETRADIANT_FOLDER/games/purity.game to adapt the paths.
Then you can launch netradiant and select purity.
You edit your map, I started with this tutorial : http://www.youtube.com/watch?v=N-Roq1EXxPc
Then you save it under nameofthemap.map, and you do Build->final (I use the line with (final), I don't know the utility of the other lines)
Once your map compiled (when your map starts to be big and complex, the compilation will take more time), you can play it in purity. Launch the game in run mode and in the quake terminal type "\map nameofthemap".
If you use my aur package, you can use "purity-zen" to graphically select the map to use.
My maps (extract them in ~/.purity/base/maps/ under GNU/Linux) :