The Color Orange
In the Netherlands, today is Queen's Day (or Koninginnedag in Dutch). The Dutch love the color orange, and this is never more obvious than today when orange is a ubiquitous sight in Amsterdam and around the country. Therefore, today's photo idea is the color orange. (Fun fact - the Netherlands obsession with orange comes from the name of the Dutch royal family - The House of Orange.)
If you aren't celebrating with the thousands of people wearing orange, don't worry, there are plenty of other orange objects to point your camera at. Besides the obvious one (..the fruit), there are also orange flowers, orange butterflies, orange cats, orange shoes, orange shirts, orange sunsets, and Orange Crush.
Example:

Photo Credit: Mondayne via Flickr
The Color Blue
Today's photo inspiration is "the color blue". This is a rather broad concept that can be interpreted many different ways. Be creative!
Pictures of the ocean and the sky are obvious choices. Your favorite blue sweater. Blue jeans. Blue M&Ms. Or maybe this would be a good time to try out a blue color filter. You could also try editing a photo into black and white except for one blue element. For a tutorial on how to achieve this effect, see Mono, with a Dash of Colour.
Example:

Photo Credit: Ehsan Khakbaz via Flickr