The best way to keep paper in an organized fashion is to use files. The cheapest are manila and I love those for the everyday business of life. But when it comes to special projects why not have a little fun? You can find folders in bold primary colors and in soft pastels. I've seen polkadots and scenes from famous cities. As you know I am a huge advocate for dogs so these caught my eye. These are at The Container Store. Google phrases like 'fun file folders' and see what you discover.
There are other ways to have fun with your files. Use the Feng Shui meaning of colors for specific areas of your files. Yellow for example is the color for Health so you could put your family's medical files in yellow. Or you could use them for a new long term project that you want to have a 'healthy start.' Or you could put those files into Red which is the color of Fame & Reputation (in other words how you are perceived in the world) with the intention that this project will be known far and wide. This way of playing isn't of interest to everyone but it demonstrates how much fun you can have getting organized. Think outside that boring box you have in your head where all concepts for getting organized reside. Crack it open like a pinata and find the treasures you didn't realize were there.