SharePoint 2010 PowerShell Useful Scripts

Get Content Types in a Site collection
$site = new-object Microsoft.SharePoint.SPSite(http://ww3.sp.demo.dev/)

$web = $site.rootweb.ContentTypes
ForEach ($id in $web)
{
'"' + $id.Name + $id.Id + '"' Out-File "d:\logfiles\contenttypes.txt" -append
}

Delete a List Instance
$site = new-object Microsoft.SharePoint.SPSite(“http://demo.dev/”)
$web = $site.rootweb
$list = $web.Lists["Orders"]
$list.Delete()
 
Run all time jobs 
$timers=Get-SPTimerJob|{$_.isDisabled -eq $false}
foreach ($timer in $timers) {$timer.RunNow()}
View ULS data for a CorrelationId
PS C:\Users\PaulB> get-splogevent ?{$_.Correlation -eq "fe45a7cd-e91b-4ad3-80dc-50cd2a238c6a"} select Area, Category, Level, EventID, Message Format-List 
Run the SharePoint Health Analyzer
$jobs = Get-SPTimerJob | Where {$_.DisplayName -match "Health Analysis Job"}
foreach($job in $jobs) {
  Write-Host "Running" . $job.DisplayName
  $job.RunNow()
}

Read an XML file:

Not all jobs are fired automatically so you can run all the SP Health Analyzer jobs using this PS cmd.  Ensure server can deal with extra load (run out of hours if possible).
Ari Bakker

Turn On-Off Publishing Workflow
John Livingston
PowerShell Basics
Zach Rosenfield's - Farm settings, retrieve solutions, basic SharePoint operations
Gary Lapointe
Blog

Brian Lalancette
AutoSPInstaller - Installation of SP2010
Use Windows PowerShell to Display Service Dependencies

Adam Preston
Blog
Disable Loopback in IE - New-ItemProperty HKLM:\System\CurrentControlSet\Control\Lsa -Name "DisableLoopbackCheck" -Value "1" -PropertyType dword

Todd Klindt
Blog

PowerGui
PowerGui SharePoint reference card
Download PowerGui

Add the SP cmdlets to PS window
Add-PSSnapin Microsoft.SharePoint.PowerShell

Get Help about PS Cmds
PS> Get-Help Get- SpWebapplication

http://thuansoldier.net/?p=1559

Updated: 23 Oct 2012
Add a local user account

Add an account to AD and add the account to a group.

Apologies if I have ripped script directly.  I don't have the source for a lot of the work these help scripts are based.  On pls let me know if I need to credit a source.