Weird night. 
First I was woken up at 2.30 am by the phone ringing. Except it didn't ring.
(I have had this happen before, and also been woken by the doorbell, but the doorbell didn't ring and there was nobody at the door.)
Then abruptly woken again at 5.30 am by something falling onto the hard floor. Except nothing fell and the floor is mostly carpeted. I even got up and wandered around looking to see what had made the noise.
I couldn't get back to sleep so now l am both puzzled and annoyed.