I had mine last year at about this time. I had to be there at about 8 or 8:30 PM. They had me not drink anything caffeinated after mid-day so I'd sleep (ha!). EEG leads glued to my scalp, so I brought a little bottle of shampoo with. They had glue remover ready in the morning though. EKG leads on my chest and monitors on my legs to check for restless legs syndrome. A tiny monitor on my cheek for eye movements. A band around my chest to monitor your breathing and they audio and video taped it. I had to go two nights, once for the sleep study and once for CPAP titration, but some centers can do it in one night. At Loyola (Chicago) the sleep lab is in the outpatient cancer center, so I was awakened around 5:30 AM - up and out because the first cancer patients' care starts at 7. It's pretty hard to rest with all those leads and wires - plus, it's a hospital bed with a mattress about as thick as a piece of paper. But it was worth it because I sleep better with the CPAP.