I like this project because it doesn't involve much thinking, but the result is still bright and interesting. You just fold your paper in half (hot dog style) and then in thirds the other way. I did mine with warm and cool colors, but that's optional. Here's the link to the original idea at Art Projects for Kids.
This project also got me interested in Kandinsky. Here's a link to a page that has some of his work. And here's a short section I copied from Wikipedia that really interested me:
It was not until 1896, at the age of 30, that Kandinsky gave up a promising career teaching law and economics to enroll in art school in Munich....Also in 1896, prior to leaving Moscow, he saw an exhibit of paintings by Monet and was particularly taken with the famous impressionistic Haystacks which, to him, had a powerful sense of colour almost independent of the objects themselves. Later he would write about this experience:
“ That it was a haystack the catalogue informed me. I could not recognize it. This non-recognition was painful to me. I considered that the painter had no right to paint indistinctly. I dully felt that the object of the painting was missing. And I noticed with surprise and confusion that the picture not only gripped me, but impressed itself ineradicably on my memory. Painting took on a fairy-tale power and splendour.