My gym is pretty basic so were always trying to improvise for lack of equipment. One exercise that I couldn't figure out how to do was Donkey calf raises.
Now Ive seen pics of Arnold doing them with franco and Another pro sitting on his back but I wasnt willing to quite go that far. Basicly I was stuck with standing and seated raises until my sister of all people told me a way to do it.
She mentioned that you could grab a dip belt, strap on weight, get a wood block for raises and adjust the bar on the smith machine to grasp while bent over.
I did it yesterday and it worked VERY well. It provides an additional stretch in the calf and also works well to hit the gastroc. a bit different.
Try it out some time, you'll get weird looks but it works.