I had pretty bad bruising around the back of the knee -- it was almost deep purple. Kinda scary looking, but both doc and PT said it was quite normal as the Cryo-Cuff pushes all the blood to the back.
Tim, I can sympathize on the CPM boredom. I situated myself on the living room floor in front of the TV, and had my laptop with me. Even then, I was going stir-crazy looking out the window. And just sitting on the floor for 2 hours at a stretch were a pain in the butt, literally!
Mike, what you mention about everyone being different is very true. Not only is everyone different physiologically, but everyone has slightly different injuries. I know someone who was hiking at 1 month, and another who wasn't off crutches for 2 months! To complicate matters is the difference between different surgeons and PTs. It seems like ACL recon and rehab is still an emerging field, where new things are being "discovered". So depending on how up-to-date the doc/PT is with the latest thinking could also affect recovery.
As posted above, I was on the CPM machine the day of surgery. I had a few degrees of hyperextension, and was at 100 degrees of flexion in a few days. Extension is the critical thing to get back ASAP after surgery -- flexion will almost always come back with time (as swelling reduces). Regarding crutches, my doc said I'd be fine putting weight without crutches -- the only reason he wanted me to use them was for balance, so that I wouldn't fall and re-injure something.
Regarding pushing too hard in rehab, yes, it is definitely a possibility. Because we are so active, we want to get back to full fitness. But at the same time, being active, we are also probably pretty aware of our own bodies, and the bio-feedback we get. I think we can usually tell the difference between good pain and bad pain. That's one of the reasons I got off pain meds as soon as I could -- because I wanted to feel anything that was my body's way of telling me to stop, instead of being numb to it. I also talk to my PT a lot about the different feelings I get doing different exercises and activities. It's amazing how you notice the subtleties and complexities of something that you took for granted, like walking!