Allen doesn't love sleeping at night. This is most likely because he LOVES sleeping during the day. You say - "keep him up for longer stretches during the day and he'll sleep better at night".
I say - "Great plan. Here's how it's going so far:"

Here I am bouncing him (almost violently) on my legs to keep him awake.

I had to stop to take the picture . . . but here I am rubbing his hands, fists, face, and sternum to keep him wide eyed and alert.

Trying several techniques at once here - taking him outside into bright light, fresh air, and tickling/poking him.

Laying him at awkward and seemingly uncomfortable angles. Some say this one works like a charm.

The baby book says sitting him upright will cause his eyes to just "pop open" like a baby doll. Riiiight.