I was thinking about this last night and I think it would be better as a critique.
The only rules are that the photos need to be taking outside, at least a 1/3 of the photo needs to have your color (solid, tone, pattern) and only one of the photos can be of a flower.
Other than that it can be anything. Buildings, cars, animals, street signs,... be creative..
Working on a date.
Go outside, and take pictures.
Choose a color, and shoot only objects of that color.
This is something that can be done in Adobe Photoshop Picaso.
Send me 4 of your photos with the "Color Challenge" as subject to [masked].
Tell me your color.