I thought, "this'll make a great puzzle game." You'd be a building demolition contractor, with the goal of blowing stuff up as cheaply and efficiently as possible - with the money you make, you can buy bigger explosives, new tools, etc. and be able to land bigger jobs.
So I came up with a prototype. You'd start with the lowliest jobs, like sheds and dog houses - and work your way up to skyscrapers. Unfortunately I never got past doghouses.
The fatal flaw - too unpredictable. The way the pieces fly apart in the physics simulation are pretty random. Beyond some basic logic like "put bombs at the base of the building" there wasn't much you could do to influence the outcome, except trying a bunch of random placements. Not real fun.