It's Time

One of the scenes shown in the movie trailer for "Zombie Dinner Party," namely the one in which several zombie hands break through a wall in order to grab a police officer, is reminiscent of a scene from 1985's zombie movie Day of the Dead. The character of Sarah, an American researcher living in an underground military bunker, walks towards a wall in order to change the date of a calendar only to have several zombie hands burst through the wall. Both the police officer and Sarah are located in a similar white room with neon-lights. Also of note is the fact that both scenes involve sleep: the police officer is woken up by the zombies and Sarah was merely dreaming the zombie attack and is woken up from it.

When Rigby was climbing the bookcase for the clock he was looking straight at it. He should've easily been able to read the time, however he doesn't. And if he didn't know how to read analog clocks he shouldn't have even been trying to grab that clock anyway.