While on the topic could we have a single click way to move to after midnight?
Currently the only way is to select the next day, wait for the page refresh, then select early morning and wait again. Really tedious when looking for shows around midnight!!

Perhaps a pair of "minus 6 hours" and "plus 6 hours" buttons/arrows/whatever? That should be easy to add.
Personally I think your four time blocks should overlap by at least an hour (ie midnight-7am, 6am-1pm, midday-7pm, 6pm-1am). Again this would make it easier to find shows near the boundaries (just like street directories always overlap their map pages).