Me and my friend tried to get through Warhol's "Empire" at one time (8 hours of staring at the Empire State Bldg), but only made it two hours in.
Oddly, I think he released a silent version, too
A cohost of a movie podcast I listen to (Horror Vanguard) watched all of "Logistics" (2012). The runtime is 35 days and 17 hours, and covers in real-time the manufacture of a pedometer in Shenzhen and its shipment to Stockholm (but in reverse-chronological order, the film-makers travel from the store where they buy the gadget, to the factory, via container ship).
I mean, obviously he had it on in the background while doing other stuff.