Do anything other than study on Sunday. Relax, go see Harry Potter, ANYTHING. Taking a test the day before will do absolutely nothing. I've heard from everyone and anyone that's taken this test that it's a complete waste to do anything the day before. By that time, it's extremely unlikely that you'll learn anything new, and whatever skills you use for the lsat, like for games, well, if you don't know them by the day before the test, you probably won't know them anyway. You'll probably feel much better and perform better after taking a day off. Your mind will be fresh, you'll be more relaxed, and, if studying has become a complusion for you now like it has for me, after taking a day or two off, you may actually be excited and geared up to take it.
That's what I'm hoping anyway! I'm taking two tests Thursday, and a full, 5 section test with writing sample on Friday afternoon, and then Saturday and Sunday will be FREE!