set text opaque
get the system time and then just get the hour for example
a$=get time$()
hour=val(time$) <<< returns the first number up to the colon
then just use the hour value to alter the background, either gradualy or suddenly, eg if you have a skysphere
texture object skysphere,hour <<<where you have images from 1 to 24 for the hour
you can get more segments of the time with the correct string commands if you want more precision, just use left$ to strip off the first three digits (the hour and colon), then get the minutes the same way you got the hours.
if there is one thing I can NOT tolerate, it`s intolerant people.