Painted wood floor: fill in any large gouges or scrapes, and sand the entire floor lightly. you can use nearly any paint on the floor, but if you're concerned about it rubbing off with traffic, talk to the people in the paint store/department. you can also get clear acrylic sealer to paint over the floor once it's dried and once cured, it'll protect the paint job.
Back-of-Door Organizer. The back of a door into a utility room or closet makes a handy hanging space. But most doors don't offer a good mounting surface for hardware. The solution is to screw a piece of 3/4-in. plywood to back of door. Add construction adhesive for hollow-core doors. Cut plywood 3 or 4 in. shy of door edges to avoid conflicts w/doorknob or hinges. Mount as many hooks, magnets and other storage gizmos as you like.