Sometimes you have a really cluttered desktop, and you want to clean it off, but you don't have time (or you're just plain lazy). That's where this hint about hiding/showing your desktop via a service comes in.
First of all, open Automator. When you're presented with the options sheet, choose Service. After, in the banner of the action, make it say: 'Service takes no input in any application.'
Now, drag in a Run AppleScript action from the Utilities category. Paste the following text in:
on run {input, parameters}
set myAnswer to ((do shell script "defaults read com.apple.finder CreateDesktop") as integer) as boolean
do shell script "defaults write com.apple.finder CreateDesktop " & (((not myAnswer) as integer) as string)
do shell script "killall Finder"
end runMac OS X Hints
http://hints.macworld.com/article.php?story=20100804092806364