Actually, it's pretty boring. I've done it 3 times for 2 brain surgeries. The first time I had one in the second day. The second time I was there 5 days and had not a single sz. I had to go back and ended up having a GM on the 5th day. In my case though they needed a cp to confirm that that my sz focus was in the RTL. Auras wouldn't suffice. They didn't really like the GM either but they could tell from the EEG that it started in the RTL and then proceeded to become a GM.
Take lots of reading material because after a while the TV gets real boring. Also, they definitely monitor you. You basically have your own nurse and if you need to get up and go to the bathroom she comes in and stays outside of the bathroom just in case you end up having a sz while you're up.