I cracked one of my ribs about 2 months ago and I'm finally back to 100%. Lesson learned: 45* leg press machines are a great way to hurt yourself. I cracked one of my lower left ribs near my kidney.
For me, it was about trying different types of exercise to see what did and didn't put pressure on the rib while it healed. Oddly enough, running didn't aggravate the injury so that's what I focused on. Eventually, I started doing isolation-type exercises with lighter weight. Fortunately, I'm back to squatting/deadlifting 400+ lbs for reps without any pain, but I made sure I let everything heal, gave it another 2 weeks and then started lifting heavy again.