I've been doing my kettlebells and one key thing with kettelbells is good squatting form. So one of the exercises you do is squatting facing the wall, working up to the point where your toes touch the wall.
I thought it wouldn't be that hard... uhh it kicks my butt. I get extremely tired doing it.
The idea is to be able to pick up a kettlebell with your toes touching the wall without any other part of your body touching the wall. Also, you have to keep squat form, flat back, stomach tight, toes up, toes only slightly turned up, etc.
So anyway, this exercise has reminded me of how much my squats suck

I have been practicing this exercise though and I'm getting better and lower each time.