i looked up the acorn squash ; it looks like the green pumpkins to me, and it turns out it's in the
Cucurbita pepo family which is the same as the green pumpkins and as the pātisson (
pattypan). i just tried a pātisson (the four seasons guy recommended it since i love the butternut) but i'm not so much a fan, although i suspect it can be good cooked differently. however if you don't like butternut because it's too sweet you should try the pattypan, it's not as sweet. plus they're so pretty.