TV freezing up

I have noticed that between 8pm and 9pm my ability to change channels, use the guide or in any way use the remote freezes up. It take sometimes up to 30-60 seconds for the box to respond to remote control input. I am stuck on a channel until the box decides to kick in. I have shut of the TV and cable and restarted. It seems to happen only during this hour, before and after that time I have no problem. Has anyone else noticed this? Can anyone explain this to me?