A YouTube group called Pomplamoose just uploaded a new mash-up cover of Pharrell songs that's pretty good. And the video they made for it is EQUALLY good.
The songs are "Get Lucky", "Happy", and "Lose Yourself to Dance". And for the video, they projected different images on a bunch of white foam-board. (Search for "Pharrell Mash-Up - Pomplamoose." They start doing the effects at :31.)