My favourite is Cold Dark Matter: an Exploded View - here Parker put household items in a shed and got the army to blow it up.. and with the fragments left from the destruction, she created the piece; suspending the particles from the ceiling with see through wire. I think it's amazing, and the shadows cast over the room add so much to the visual experience.
I was looking through my old A-Level art books earlier, and saw pictures of my attempt at a bit of Cornelia Parker. In my home town there is a derelict zoo and amusement park. It is now filled with bits of decaying wood, metal and mesh, there are some quite beautiful things up there (if you like that sort of thing). Anyway, my method wasn't as drastic as that of Parker - I just put some bits in a shoe box and took a hammer to it. I then hung the little fragments off a light fixture and took some pictures. The quality isn't that good on these though.