When all of the pieces of a kit have been punched out, what remains is often an interesting composition of positive and negative space. I've been saving the remnants, and turned two sets into interesting wall art.
A dinosaur kit from Michael's got me started. I watched young cousins assemble the animal but was fascinated by what was left over. Eventually it came together as Jungle Beat.
A Greenleaf Dollhouses kit -- I don't recall which one -- inspired City Lights. Not as organic, a different vibe altogether. (Click the photo for a larger version.)