Check out some of these books for lots of ideas and inspiration to get you started. My Art Book shows you how to make fantastic faces based on paintings by Giuseppe Arcimboldo (c.1527-93). He was an Italian artist who could paint ordinary pictures but is best know for his weird faces made up of plants and animals.
Maybe you would like to have a go at making a mosaic like Diego Rivera (1886-1957). He was a Mexican artist famous for his mosaic wall art.
Even something simple like rock painting, frottage, or t-shirt printing, there is heaps to keep you busy.