I usually have a lot of applications open that I use from time to time, not too frequently. It may be email client, one of my browsers or a PowerShell console that I use for some tests, conversions, etc.
Why not to hide them and bring to front only when you need it? Just press a hotkey and the window is shown. Just press a hotkey and the windows is hidden (you don't see it in your taskbar, but the process is running).

(not only) For this purpose I use AutoHotkey. If you don't know this tool, it's worth checking. It's not just a simple mapping "if this key is pressed, run application at this path"; you will see a pretty scripting language.

Show / hide PowerShell console

As I said I have usually at least one PowerShell console open. Most of the time I use browser or Visual studio, so the Posh window might be hidden. How to do that?

First I need a way how to identify the Posh console. The window class would be ok, but Posh console has the same class as the window where cmd.exe is hosted. Besides that if more than one Posh console is open, I would not be able to distinguish between them.
That's why I make the window title unique:

[1]: $host.ui.RawUI.WindowTitle = 'myuniquewindowtitle'

From now on the title of the console is 'myuniquewindowtitle' (check the taskbar for example).

Then I will add a function to AutoHotkey script that hides or shows the window depending if it is visible or not.

LAlt & `::
  DetectHiddenWindows, on
  PoshWinName := "myuniquewindowtitle"
  IfWinExist, %PoshWinName%
    IfWinActive, %PoshWinName%
      WinHide, %PoshWinName%
      WinActivate ahk_class Shell_TrayWnd
      WinShow, %PoshWinName%
      WinActivate, %PoshWinName%
  DetectHiddenWindows, off

Just press left alt and tilde and you will see that it works.
I saw base for this script in some comments, thanks for that.

Similarly you can hide and show any window. If the window title is not always the same, you can specify it by window class – AutoHotkey tool will help you with finding the name of the class.

Meta: 2009-12-23, Pepa