The art of blending is more widespread than you might think. In fact, it is found not only in the culinary world but also in the arts. In films, as in music, works may contain more than one genre, or mix several stories. A love story may have a comic side, a touch of science fiction and just the right dash of horror. All in the same film. These are cross-genre movies, virtually blending in the form of a film. Examples include dark fantasy (horror and fantasy), tragicomedy (tragedy and comedy) and the most popular of all, romantic comedy.   This mix of film genres in a single movie has been around for a long time but its fame has grown exponentially during the last decade. To avoid boring audiences with the familiar history lessons and to offer products that are fresh and and new, Hollywood is coming up with more and more fascinating, unusual scripts, using this very technique. Perhaps before too long we will find ourselves watching a musical documentary or a spaghetti western fantasy. Blending on the big screen may have some wonderful surprises in store.