Works of art are the (usually) tangible result of the activities of artists. Some types of artworks include:

"Works of art" can also include non-tangible outputs of creative endeavors, such as

and a whole host of other, sometimes bizarre, sometimes mundane, things that people do.

Artists are very creative and unpredictable by their nature, and come up with things that are hard to classify! As the art node says, "Almost anything can be art."