If you're one of those anal types who likes to see their gaming library in a nice, organized display, things like storing Wii Sports in its cardboard case really sticks in your craw. Fortunately for you and your craw, the Cover Project has you... uh, covered. Contributor "megashock5" has created a custom art file (about 3.5 MB) for you to print out and shove into the nearest white DVD case, thus silencing the constant nag of your OCD.
If you don't have a white DVD case, take 4ColorRebellion's suggestion. Either spend the penny on a Wii preview DVD from Target or drop a buck-fifty on one from the official Nintendo Store. Classy!