Excel add-in for array manipulation.
Download xllarray.zip, extract all files to any folder, and open
Select a cell containing a function, start the Function Wizard, and click on
Help on this function to see the documentation.
Lean on F9 a few times to see things in action.
If you are using Vista or Windows 7 you may need to right click on
xllarray.chm, choose Properties, and Unblock this file.