If you've got $56,000 lying around (and really, who doesnt?) you can get yourself this full size Camarasaurus Dinosaur Replica. It stands 6 meters high and 17 meters long, and is basically the coolest possible thing you could ever put on your lawn. Unless, you know, you dug up Elvis' grave and put his corpse on your lawn. I guess that might be cooler.
NOTE: If you also purchased this thing, you would officially be my king.
EDIT: I had an additional zero when I converted the mm to meters. No, this thing isn't larger than a football field.