Hmmm...I don't think I strictly "crammed" anything, but I did spend the last 7 days of my studying reviewing what I had already studied. Your mileage may vary, but these are the subjects I "crammed," and for me in particular, it worked well:
1) Pharm, pharm, and more pharm - but pretty much only what was in First Aid; essentially, in the last days I was just making sure that I knew the basics cold. I reviewed the pharm section in First Aid, and all the pharm relating to each system. This was REALLY useful for my test. Everything else I remembered was bonus, but not absolutely necessary.
2) Basic neuroanatomy - where the globus pallidus, caudate, putamen, hypothalamus, hippocampus, dentate gyrus, etc. were in relation to the lateral and third ventricles
3) Neoplasms of the reproductive and CNS systems
4) Quick review of personality disorders and defining criteria
5) I reviewed UW ethics questions, and what was in First Aid
6) Review of what happens in each segment of the nephron; I found it most useful to focus on what transporters are located in which segments - everything else that happens in response to changes in electrolyte concentration/hormonal influence/GFR followed logically from that.
7) Reviewed acid/base balance - pulm. and renal interactions
All in all, I reviewed the subjects that I felt least comfortable with. In the end, what you cram and how much it will help you will depend on what you yourself think you need to cram in at the last minute, and what's on your test (and you can't predict what's going to be on your test). But you CAN browse the boards, figure out what is essential to know, and figure out which of those things you are least comfortable with.
Good luck!