So I'm remembering that ages ago (probably in the early to mid 90's) I was watching either a TV show or a movie. It involved children/teenagers moving into a different world/alternate reality that was run on a clock timer. I believe they had to return to the normal world when the clock (a big futuristic looking grandfather clock) otherwise they'd be trapped in the alternate world or something similar.
I also vaguely remember there being some sort of person in the alternate world who would help the children and some villains there as well.
The alternate world they went into (from what i remember) was a city environment but very closed in, lots of walkways between buildings, almost claustrophobic and I think it may have had a red/orange tinge to those scenes but i'm not 100%.
That time frame of early to mid 90's may also be incorrect but I definitely wouldn't say it was later than 2000.