My friend told that once when he woke up after some drinking and partly opened his heavy sleep filled eyes, apparently it was a cloudy day because all he could see was grey and then a moment later it started raining on him, he just closed his eyes again in misery until it occured to him, that if he was sleeping at home, then why was he getting wet?
When he lifted his head up he realized that the grey was the concrete curb and the rain was a sprinkler.
I knew a guy in college who woke up after a bout and was in a panic because he thought he had gone blind. Fortunately, he soon realized that the problem was that his eyelids were sealed shut because he had become sick upon himself. (That sounds stilted, but I did not want to gross anyone out.)