Summary: Use a cmdlet from the PSCX module to get your system uptime.

Hey, Scripting Guy! Question How can I easily find my system uptime if I have the Windows PowerShell community extensions (PSCX) installed?

Hey, Scripting Guy! Answer Use the Get-Uptime cmdlet from the PSCX module:

Get-Uptime

Note  For more information about the Windows PowerShell Community Extension project, see my post, 
Install the PSCX and 80 New Cmdlets to Ease PowerShell Use.