I don't get sleepy at work too often, there's usually too much to do. But I spent the first five hours of my work day trying everything I could think of to get a new server to boot, until it finally became clear that it had just shipped broken. So that was five hours of everything I could do, amounting to absolutely nothing. Pure frustration, in other words.

So I get back to the office and find I'm due in a two hour meeting about database architecture - a subject about which I know relatively little, but have to oversee stuff, so I can't just skip out. So I'm sitting there, comprehending almost nothing, as two people with different incomprehensible accents talk about arcana. And I start to get sleepy. And I get to that not-asleep-but-not-rational stage that sometimes happen, when the brain connects together two completely different things from wildly disparate quarters of consciousness, and goes, "HA HA! These two things make sense together!" Until finally I get from data structures, to random nonsense. My approximate train of thought, "Oh, I see how that makes sense in a 2-D data structure paradigm, but if we extrapolate to 3D space somewhere down the line, we have no way to simulate star clusters off the galactic plane."

At that point some other quadrant of my brain was going, "Wait a minute, that doesn't make any sense at all. You're falling asleep." So I snapped out of it and paid attention again. But man, my brain comes up with some loopy shit.