Barbell Back Squat
15 reps of light weight
12 reps - increase weight to light-medium
10 reps - increase weight to medium
8 reps - increase weight to medium heavy
8 reps - increase weight to heavy but manageable

Notes: Increase weight each set. Move from light to heavy weight, but it should be a doable heavy weight for you. Rest 2 minutes between sets. Record weight used for heavy set of 8.