As long as there isn't a cat walking across my face, insisting that it's play time, I try to take a deep abdominal breath, exhale, and think "sleeeeeep" along with the exhale. I also try to gently roll my eyes upward to give them a little nudge in the right direction. If that doesn't work, I just get up and go to the bathroom

By then, the cat knows I'm up, and a whole new battle begins.