On 20th December 2013 Sebastian Kügler released the Plasma 2 Technology preview. Plasma 2 brings many improvements and and big changes in Plasma Workspace, KWin, and other parts of desktop.
The good news for KDE SC users is that they can now test and try the preview in many ways. Before you want to try it out, check out this video.
Plasma 2 Technology preview depends on the Qt 5.2 so you need to install it first. OpenSUSE provides the Qt5.2 packages in KDE:Qt5.2 repository. To add this repository enter this command,
sudo zypper ar -f http://download.opensuse.org/repositories/KDE:/Qt52/openSUSE_13.1/ KDE:Qt5.2
After that you need to add KDE:Unstable:Frameworks repository to openSUSE. To add KDE:UnstableFrameworks repository enter this command,
sudo zypper ar -f http://download.opensuse.org/repositories/KDE:/Qt52/openSUSE_12.3/ KDE:Unstable:Frameworks
After that you need to install kf5-session package. This package provides entry in login manger to log in the Plasma Workspace 2.
Kubuntu / Ubuntu
Project neon provides the packages for Ubuntu/Kubuntu in project-neon5 PPA. To add Project Neon 5 PPA and install Plasma 2 packages run this command.
sudo add-apt-repository ppa:neon/kf5
sudo apt-get update
sudo apt-get install project-neon5-session
This will provide the entry in login manager to log in the Plasma Workspace 2 session.
Project neon 5 ISOs
Project neon 5 provides Live CD which have Plasma Workspace 2 pre-installed and you can explore the Plasma 2 Tech preview. Currently only x86_64 images are available to download from here. If you want i686 build you can checkout scripts here.
Compiling from source
To compile Plasma Workspace 2 from you can find instructions on KDE Community wiki here http://community.kde.org/Frameworks/Building.