I would take photos of different outfits with different color schemes. I could go a few different ways with this one. I could have all of the clothes modeled by the same person, someone that I know, maybe even myself. Or I could go out on the streets and find people with nice color schemes. I could also use my friends as models and have all my friends each wear a different color scheme made up of colors from their wardrobe. This could, and would, also incorporate the background colors to help with the over-lying color scheme of the images.
Ties & Suspenders
I own a heck of a lot of ties and suspenders, I could incorporate ties and suspenders into a neutral-based outfit like black shirt and jeans, or white shirt, or some shade of gray shirt. But then focus on the ties and suspenders making the color schemes, along with the background color(s). This one probably would be a bit harder to pull off, but I really like this idea.
I am not an avid book reader, but now-a-days I love to look at books, and their covers and the text inside. Pretty much every graphic design and typographical aspect of the book. But books can have gorgeous covers. I would not be able to use all the books that I have because I do not have enough books to do this, but Barnes & Noble sure does. That may be a little hard to be able to pull off, however.