You know all those beautiful variegated yarns that you have? You know the ones. You saw them at your LYS and bought it. Hey, it's only 15 bucks. Why not right? 
Or maybe you're a dyer. You've dyed single skeins that are never enough to actually make something.
Take a peek at my dilemma...
Certainly is a pretty dilemma. I need to make a pattern that uses all that without looking like a gaudy sweater from the 80's. Hm.