I spend the day golfing before major exams. Don't touch an ounce of study material. Did it before MCAT and Step 1 and was very happy with the results and I'll be doing it this coming Monday before Step 2 CK on Tuesday. And yes, I suck at golf but it kills an entire day, I take a non-medical friend so I'm not tempted to talk about material, it's relaxing, and I'm tired enough from walking the course that sleeping the night before an exam is no problem.
I do 10 practice questions the morning of just to warm up but don't check the answers so I don't get disheartened if I get as lot wrong.
YMMV but personally I think being calm and relaxed on test day is more valuable than one more study day after weeks of nonstop learning. I don't understand the folks who are chugging RedBull at the testing site frantically flipping through First Aid.