Apart from feeding, changing nappy, putting down for nap, cuddling, of course.
I feel like mine spends a lot of the time lying on his activity mat or sitting in the bouncy chair. We go out for a walk at least once a day - but then he's either in the ergo or pushchair. I dunno - I mean, I KNOW he can't do much, but it all feels so passive! I guess I feel like he just spends a lot of time watching me do housework etc.