How many tractors does it take to change a lightbulb ?
I remember some years back, I was the driver for a printing firm and when I'd be waiting for orders to take out, I'd be reading but my ear would often catch the sound of the printers.......they were so rhythmic and I planned to take my recording gear there and just get 20 minutes of sounds and build them into some song. I never did get round to it. But 'found sounds' aren't new and they wear thin after a while.
I just thought it was funny as all Hell. Of course the tractor won't 'swing' or have dynamics. Still, for one song you'd be talking about it for days after. I guess if it threw a rod it could still 'play', and be considered a crazy solo.