In the days when I did lots of SharePoint development, I had to work a lot with powershell.
One of the tasks I needed to do quite a bit was generating a GUID for things as a unique marker. This is what I usually use:
PS C:\> [guid]::NewGuid().ToString().ToLower()
It is a simple thing that is super handy when working with PowerShell.
One question that even I myself ask from time to time is "How do I copy and paste values from the PowerShell prompt/REPL window?". It is not a stupid question because copying and pasting in windows command prompts works a wee bit different.
How to do it can be seen here : http://superuser.com/questions/405851/copy-and-paste-in-windows-powershell