Precious will tell me when it is time to go to bed. If she thinks I have been up to late or she wants me to go to bed so she'll get attention, she'll come up next to me on the floor and will meow and then roll over on her back while looking at me with these adorable eyes and her paws above her head. I know that this means it is bed time. I know because she has me trained to know.
She started doing this when she was a kitten and so I would say "Is it bed time?" or "Are you wanting to go to bed?" and she would meow back at me and then I'd go to bed and she'd hurriedly follow me. She quickly learned how to get me to go to bed.
Do any of your cats do this?