Blender 2.59 is Released and available for install in Ubuntu/Linux Mint using PPA
The Blender Foundation and online developer community is proud to present Blender 2.59. This is the third stable release of the Blender 2.5 series, representing the culmination of many years of redesign, development and stabilizing work.
When installation finished (Press Alt+F2 and type: blender) to start blender.
sudo add-apt-repository ppa:cheleb/blender-svn
sudo apt-get update
sudo apt-get install blender
Here is the Blender Homepage
Here is Blender 2.59 release log