Nothing could be more simple to test and lab on than powershell. However not everyone likes to install and configure stuff on their local machines and if you are one of those people here is to pretty nice 101 labs for Powershell availiable for free online..

Powershell V2: http://go.microsoft.com/?linkid=9701966
10-great scripts: http://go.microsoft.com/?linkid=8958019

They take between 10-30 minutes of your time but teaches you some good stuff.
Also don’t forget to check out the rest of the online labs at TechNet Labs