NICE!!!though the machine is by far more popular, hack-squats are pretty common IMO
i thought i'd add a few to this great thread, though I didn't make these exercises up I rarely see people doing them.
Flex Lewis' Steering Wheels (plate twist?):
Basically you just hold a 45 Plate out at arms length and pretend you're steering "right" then "left," alternating directions. I can't seem to find the video where Flex is teaching this to Gaspari. I get some great deltoid activation.
Grab a couple of hexagonal dumbbells and set-up to do push-ups off of them. You then alternate 1 arm dumbbell rows as you complete push-up reps. Supposedly great for the core. Though I haven't gotten around to incorporating these into my routine, I intend to do them some day....
Behind the Back Smith Machine Shrugs
From the many pictures I've seen, and a few articles I've read, the barbell version of this was iconic of Lee Haney. I really, really like the Smith Machine version and it's a staple for my traps now.
When I think of more I'll give this a good bump
I use all of these and they all work fantastic. Great addition!