Plasma/Live Images
Try and install Plasma from a live medium provided by several Linux distributions.
Shipping the latest code from Git
KDE neon
KDE neon builds Frameworks, Plasma and Applications on a continuous integration system.
You can use the Developer-stable version for builds from Plasma/5.x branches or Developer-unstable version for builds from master branches.
openSUSE
Argon and Krypton are openSUSE live images shipping the latest KDE software from Git master (unreleased) for Leap and Tumbleweed, respectively.
Ships Plasma 5.12 LTS
KDE neon
KDE neon builds Frameworks, Plasma and Applications on a continuous integration system.
The developer stable edition builds from Plasma/5.12 branches
openSUSE
The latest released Plasma version is available as a live image as part of the Krypton stable image:
32 bit version and 64 bit version
Slackware
Alien BOB (Eric Hameleers) provides an installable Live image for Plasma 5 based on the development tree "slackware64-current". Login account/password are both "live". Use su or sudo to become root (using the "live" password).
Ships Plasma 5.10
Kubuntu
Kubuntu 17.10 Artful Aardvark, released In October, includes Plasma 5.10.5. The live ISO is available for download, and Plasma 5.11.2 can be installed via the Kubuntu backports PPA.