One thing I try to keep on my Mac is a clean and organized desktop. Sometimes when working on larger projects I let it slip and never really get around to cleaning it up like I should. Eventually, when I do get up the courage to try and organize all of the files into folders and subfolders, I find myself wondering where I put that one file I need at that moment and wishing I would have just left everything as it was.
DeskShade from MacRabbit is an application that allows you to cover up all of that clutter with a background image of your choice. It also allows you to require a password to unlock the computer and get back to the main desktop so you can see and use all of that clutter again while preventing others from beating you to it.