Make something in which the sense of smell is the essential component.
First thought: 'oh, that's easy, i'll just burn my dinner'.
Second thought (i blame the bouquet from day 47!) : flowers. I'd seen this style of layered collage before – where parts of the image where added on top of the original to give a 3D effect – and thought it might be fun to give it a shot. Little scrap pieces of foam core board helped separate the flower layers. As for the smell part? It doesn't really come across well via the blog, but the flowers were sprayed with perfume!