>>This would also explain why days with unusual content seem to last much much longer than others (at least that's my experience).

I've heard this explained in part because of how our neocortex works. New events tend to require the involvement of more layers of the neocortex than ones that are redundant and routine. This is part of the explanation for the time dilation we experience when surprised by something like a car crash or a thrill seeking adventure. Your mind is fully engaged much the way it was when you were younger and everything was a new experience. As your mind adapts the neocortex handles the events more efficiently; more reflexively. Your mind subconsciously ignores the sensory inputs that don't surprise you.

For this reason, it's often advised that if you want to slow down the apparent passage of time just change your routine. Granted...your neocortex would probably even adapt to this.