Now this little hack will not get a single task done or make you more productive by any stretch of imagination. Nevertheless, this fun script by Marko Kästner takes your OmniFocus tasks straight from the cache database, produces a tag cloud like image and sets it as your desktop background. Being a little hacky, making it work and automating it needs a few skills, but the documentation provided is straightforward.
If you are looking for something more productive you want to check out Marko's posts on Getting Agile Results with OmniFocus. Marko is also the brain behind the rather helpful Alfred 2 workflow for OmniFocus which I covered earlier.